On Friday, 13 July 2018 15:28:27 UTC+1, Johnny B Good wrote:> On Thu, 12 Jul 2018 17:43:20 -0700, tabbypurr wrote: > > On Thursday, 12 July 2018 19:43:48 UTC+1, Johnny B Good wrote: > >> On Wed, 11 Jul 2018 21:29:09 -0700, tabbypurr wrote: > >> > On Thursday, 12 July 2018 04:43:31 UTC+1, Johnny B Good wrote: > >> >> On Wed, 11 Jul 2018 06:44:02 -0700, tabbypurr wrote: > >> >> > On Wednesday, 11 July 2018 02:20:36 UTC+1, Johnny B Good wrote: > >> > > >> >> >> I'm posting here in the hope that I can get some guidance on how > >> >> >> to add an electric start feature to a cheap inverter generator > >> >> >> cursed by the traditional recoil pull starter (the Devil's > >> >> >> invention, imho). Apologies beforehand for what is a rather long > >> >> >> initial post but I thought it best > >> >> > > >> >> > > >> >> > You do realise that cheap gennies have very short operational > >> >> > lives, making extensive work on them pointless. If you want > >> >> > something worth tinkering with get a Listeroid from some 3rd world > >> >> > country. Tinkering is not optional & they will run for a lifetime, > >> >> > day in day out, once fully built. Listeroids also use a fraction > >> >> > as much fuel as modern junkboxes. > >> >> > >> >> Not quite as small a fraction as you might think. > >> > > >> > marketing speak > >> > >> ??? > > > > it's meaningless. And if you were to ascribe it a meaning, still > > valueless. Classic marketing talk. > > That still doesn't really make a lot of sense. I looked at the fuel > consumption graph for bio-diesel and for the 1KW point on the graph it > equated to 0.64 litres per hour which is only slightly less than the 0.68 > litre per hour figure for the 670W output level of the PGI 1200 B2. To be > fair, that's an apples and oranges comparison but I don't have a graph > for the Parkside units. > > Alternatively, at the 700W level, the Listeroid graph shows a 0.15 US > gal per hour rate which equates to 0.57 litre per hour despite the > reduced efficiency of the consumption per KWH figure which flattens out > in the range 1250 to 2500 watts at a per KWH peak of 0.5 litre per KWH of > energy generated. When you look at the 500W figure that per KWH > consumption hits the 0.98 litre mark which is likely much higher than the > Parkside's consumption rate at this production level (500W load). > > If the generator spends most of its run time operating at the 300W > level, the litre per KWH rate gets even worse leaving the Parkside the > winner in this case but, of course, that neglects the much lower cost per > litre of duty free diesel over that of petroleum (gasoline). > > Also, the Listeroid graph is handicapped by the use of a conventional > single phase 230v alternator generator head and the extra losses of a > drive belt totally absent in the case of the direct drive PM three phase > alternator powered inverter suitcase generator. > > For anyone living off-grid, the choice of a large low revving diesel > prime mover to drive a generator head (whether it's a conventional single > phase 230v alternator or a geared up three phase PM alternator with > inverter module), is a no-brainer one. However, for someone looking for > an emergency backup generator to mitigate winter outages or looking for a > more luxurious wilderness trekking experience, the lightweight suitcase > inverter genset becomes the no-brainer option (that 1KW Parkside unit > only weighs in at a mere 13Kg!).Do you have links to the graphs & specs of the units you're comparing?> >> >> However, they can be run on duty free diesel for about half the cost > >> >> of a petrol/gasoline generator. Indeed they're not fussy about what > >> >> fuel oil you choose to run them on so you have a lot more fuelling > >> >> options. > >> >> > >> >> Thank you for that sage advice. I do appreciate what you're saying > >> >> but > >> >> unfortunately, I'm not trying to live off grid and nor do I have the > >> >> space to install such venerable machinery. On top of which, the > >> >> standard generator heads typically fitted to these listeroids[1] no > >> >> longer suit the needs of modern day lighting and computer loadings, > >> >> particularly true in the case of my venerable Smartups2000 with its > >> >> 9.4μF's worth of capacitive loading across its mains input which > >> >> sends conventional single phase AVR controlled 230vac 50Hz > >> >> alternators into a massive over-volting state as a result. > >> > > >> > not hard to add an inductive load to protect against capacitive loads > >> > >> Yeah, I used to think that too. :-( > >> > >> Believe me, that's exactly what I tried but it failed to remedy the > >> problem. > > > > Not enough inductive current I presume. > > Judging by the effect it had on my first Parkside genset, I'd say it had > provided ample inductive current. I'd forgotten that I still had it in > circuit when I hooked up the first generator to the cable leading into > the basement to my Smartups2000 (not yet plugged into the business end of > that cable), so was surprised when the generator started labouring when I > plugged it in.> Unfortunately, it never occurred to me to verify the claimed overload > wattage calibration setting so I landed up with the one that signalled > this state at the 980W mark rather than the expected 1030 to 1050 watt > mark. > > I suppose it's just possible that the other could have been set exactly > the same, possibly all of them, in which case I'd be left to consider a > calibration error on my test equipment being on the wrong side of the > +/-3% accuracy tolerance range (both my analogue and two digital > wattmeters being within 1% of each others' readings in the 1 to 1000W > range makes this unlikely though not impossible). > > If Lidl ever put these B2 models back on offer at the same 99 quid > price, I'll be snapping a couple of them up for testing. At that price, > it's well worth holding a spare in reserve anyway. > > Normally, with such miscalibration issues as this, I'd be adjusting the > relevant trimmer. Unfortunately, the inverter module used is completely > devoid of any such trimmers - presumably they're preset in the factory > (possibly via a JTAG connector - there are a couple of unused header > blocks that could be candidates for this function).Likely no setting option other than by replacing a resistor.> > with respect there are easier ways. I'm sorry if pointing that out upset > > you. > > Not annoyed, irritated? yes! but annoyed? no. > > Ok, suggest an 'easier way' then.I did, a wacking great inductor. Inductor i needs to exceed capacitive i. A pair of MOTs in series would be my first thought. I know you said it didn't work for you, but consider this. If inductive i exceeds capacitive i, the genny sees zero capacitive i. How then can it overvolt due to capacitance? IOW I suspect an unfound flaw in the implementation somewhere. NT
Electric start for suitcase inverter generator by using its alternator as a BLDC motor?
Started by ●July 10, 2018
Reply by ●July 13, 20182018-07-13
Reply by ●July 13, 20182018-07-13
On Friday, 13 July 2018 16:17:30 UTC+1, Johnny B Good wrote:> It might turn out to be a "Red Herring" chase on my part. Continuing > with the fishy pun theme, I'm obviously still 'floundering' around with > this project so any assistance in the matter of BLDC motor controllers to > convert a 350v three phase PM alternator into a starter motor would be > greatly appreciated now.Has salmon not done this before? If so, eel know how to make it work. NT
Reply by ●July 13, 20182018-07-13
On Fri, 13 Jul 2018 15:55:27 -0700, tabbypurr wrote:> On Friday, 13 July 2018 15:28:27 UTC+1, Johnny B Good wrote: >> On Thu, 12 Jul 2018 17:43:20 -0700, tabbypurr wrote: >> > On Thursday, 12 July 2018 19:43:48 UTC+1, Johnny B Good wrote: >> >> On Wed, 11 Jul 2018 21:29:09 -0700, tabbypurr wrote: >> >> > On Thursday, 12 July 2018 04:43:31 UTC+1, Johnny B Good wrote: >> >> >> On Wed, 11 Jul 2018 06:44:02 -0700, tabbypurr wrote: >> >> >> > On Wednesday, 11 July 2018 02:20:36 UTC+1, Johnny B Good >> >> >> > wrote: >> >> > >> >> >> >> I'm posting here in the hope that I can get some guidance on >> >> >> >> how to add an electric start feature to a cheap inverter >> >> >> >> generator cursed by the traditional recoil pull starter (the >> >> >> >> Devil's invention, imho). Apologies beforehand for what is a >> >> >> >> rather long initial post but I thought it best >> >> >> > >> >> >> > >> >> >> > You do realise that cheap gennies have very short operational >> >> >> > lives, making extensive work on them pointless. If you want >> >> >> > something worth tinkering with get a Listeroid from some 3rd >> >> >> > world country. Tinkering is not optional & they will run for a >> >> >> > lifetime, >> >> >> > day in day out, once fully built. Listeroids also use a >> >> >> > fraction as much fuel as modern junkboxes. >> >> >> >> >> >> Not quite as small a fraction as you might think. >> >> > >> >> > marketing speak >> >> >> >> ??? >> > >> > it's meaningless. And if you were to ascribe it a meaning, still >> > valueless. Classic marketing talk. >> >> That still doesn't really make a lot of sense. I looked at the fuel >> consumption graph for bio-diesel and for the 1KW point on the graph it >> equated to 0.64 litres per hour which is only slightly less than the >> 0.68 litre per hour figure for the 670W output level of the PGI 1200 >> B2. To be fair, that's an apples and oranges comparison but I don't >> have a graph for the Parkside units. >> >> Alternatively, at the 700W level, the Listeroid graph shows a 0.15 US >> gal per hour rate which equates to 0.57 litre per hour despite the >> reduced efficiency of the consumption per KWH figure which flattens out >> in the range 1250 to 2500 watts at a per KWH peak of 0.5 litre per KWH >> of energy generated. When you look at the 500W figure that per KWH >> consumption hits the 0.98 litre mark which is likely much higher than >> the Parkside's consumption rate at this production level (500W load). >> >> If the generator spends most of its run time operating at the 300W >> level, the litre per KWH rate gets even worse leaving the Parkside the >> winner in this case but, of course, that neglects the much lower cost >> per litre of duty free diesel over that of petroleum (gasoline). >> >> Also, the Listeroid graph is handicapped by the use of a conventional >> single phase 230v alternator generator head and the extra losses of a >> drive belt totally absent in the case of the direct drive PM three >> phase alternator powered inverter suitcase generator. >> >> For anyone living off-grid, the choice of a large low revving diesel >> prime mover to drive a generator head (whether it's a conventional >> single phase 230v alternator or a geared up three phase PM alternator >> with inverter module), is a no-brainer one. However, for someone >> looking for an emergency backup generator to mitigate winter outages or >> looking for a more luxurious wilderness trekking experience, the >> lightweight suitcase inverter genset becomes the no-brainer option >> (that 1KW Parkside unit only weighs in at a mere 13Kg!). > > Do you have links to the graphs & specs of the units you're comparing?The graph is on this page <http://www.utterpower.com/listeroi.htm> Just coincidentally, regarding the weight of the Parkside inverter genset, I've just finished watching a documentary called "The Rise and Fall of Nokia" where at the very end of the final credits, the weight of a very early cell phone was quoted as being 13Kg! Its proud owner had apparently carried it around whilst on a family day's outing at the zoo and didn't receive a single call. Quite frankly, I was totally staggered by this statement having had to carry the generator from the house into the back garden and then back again, I know just how heavy a 13Kg genset (admittedly, with another couple of Kgs worth of fuel and 200g of lube oil) is to carry one handed. That guy must have had considerable upper body strength to tote such a beast around for the best part of a day is all I can think. It's an unusually "Interesting Fact"(tm) I can now quote - that it only weighs as much as an early generation mobile phone. :-)> > >> >> >> However, they can be run on duty free diesel for about half the >> >> >> cost of a petrol/gasoline generator. Indeed they're not fussy >> >> >> about what fuel oil you choose to run them on so you have a lot >> >> >> more fuelling options. >> >> >> >> >> >> Thank you for that sage advice. I do appreciate what you're >> >> >> saying but >> >> >> unfortunately, I'm not trying to live off grid and nor do I have >> >> >> the space to install such venerable machinery. On top of which, >> >> >> the standard generator heads typically fitted to these >> >> >> listeroids[1] no longer suit the needs of modern day lighting and >> >> >> computer loadings, particularly true in the case of my venerable >> >> >> Smartups2000 with its 9.4μF's worth of capacitive loading across >> >> >> its mains input which sends conventional single phase AVR >> >> >> controlled 230vac 50Hz alternators into a massive over-volting >> >> >> state as a result. >> >> > >> >> > not hard to add an inductive load to protect against capacitive >> >> > loads >> >> >> >> Yeah, I used to think that too. :-( >> >> >> >> Believe me, that's exactly what I tried but it failed to remedy the >> >> problem. >> > >> > Not enough inductive current I presume. >> >> Judging by the effect it had on my first Parkside genset, I'd say it >> had >> provided ample inductive current. I'd forgotten that I still had it in >> circuit when I hooked up the first generator to the cable leading into >> the basement to my Smartups2000 (not yet plugged into the business end >> of that cable), so was surprised when the generator started labouring >> when I plugged it in. > > >> Unfortunately, it never occurred to me to verify the claimed overload >> wattage calibration setting so I landed up with the one that signalled >> this state at the 980W mark rather than the expected 1030 to 1050 watt >> mark. >> >> I suppose it's just possible that the other could have been set >> exactly >> the same, possibly all of them, in which case I'd be left to consider a >> calibration error on my test equipment being on the wrong side of the >> +/-3% accuracy tolerance range (both my analogue and two digital >> wattmeters being within 1% of each others' readings in the 1 to 1000W >> range makes this unlikely though not impossible). >> >> If Lidl ever put these B2 models back on offer at the same 99 quid >> price, I'll be snapping a couple of them up for testing. At that price, >> it's well worth holding a spare in reserve anyway. >> >> Normally, with such miscalibration issues as this, I'd be adjusting >> the >> relevant trimmer. Unfortunately, the inverter module used is completely >> devoid of any such trimmers - presumably they're preset in the factory >> (possibly via a JTAG connector - there are a couple of unused header >> blocks that could be candidates for this function). > > Likely no setting option other than by replacing a resistor.Yes, there is that rather annoying possibility. There may even be a set of three or four trimpots on the encapsulated board hidden *beneath* the surface rather than as in the case of the Workzone's inverter module (and in photos I've seen of the PGI 1200 A1's inverter module and at least one other inverter genset), where the trimpots poke up out of the encapsulation compound specifically to allow post production adjustments. My only option to get around this little irritation may be to wait for another batch of PGI 1200 B2s to go on sale at Lidl so I can swap in a module that's been adjusted on the high side of the 1KW setting from a donor set which I can return for refund. At just 99 quid, I'd quite like to get hold of a spare as well, preferably one that's been set 2 or 3 percent above the 1KW overload warning point rather than below.> > >> > with respect there are easier ways. I'm sorry if pointing that out >> > upset you. >> >> Not annoyed, irritated? yes! but annoyed? no. >> >> Ok, suggest an 'easier way' then. > > I did, a wacking great inductor. Inductor i needs to exceed capacitive > i. A pair of MOTs in series would be my first thought. > > I know you said it didn't work for you, but consider this. If inductive > i exceeds capacitive i, the genny sees zero capacitive i. How then can > it overvolt due to capacitance? IOW I suspect an unfound flaw in the > implementation somewhere. >I reckon I'd need to shunt the line with a 250mH inductor but creating a 240vac rated 250mH inductor is a lot harder than you might think! I only managed to create a half Henry's worth of inductance which I'd hoped would be enough to mitigate the problem but it didn't quite cut it (I'd run out of 360VA mains transformer primaries by then). Even so, it must have created a 4 or 5 amp 90 degree lagging current load going by the response of that first PGI 1200 B2 to my forgetting to disconnect it from the circuit. Anyway, that major problem is ancient history now, thank Ghod! I can now concentrate on a new project, how to not let a perfectly good BLDC starter motor, currently employed only as a high voltage three phase alternator, go to waste. :-) -- Johnny B Good
Reply by ●July 14, 20182018-07-14
On Saturday, 14 July 2018 02:25:43 UTC+1, Johnny B Good wrote:> On Fri, 13 Jul 2018 15:55:27 -0700, tabbypurr wrote: > > On Friday, 13 July 2018 15:28:27 UTC+1, Johnny B Good wrote: > >> On Thu, 12 Jul 2018 17:43:20 -0700, tabbypurr wrote: > >> > On Thursday, 12 July 2018 19:43:48 UTC+1, Johnny B Good wrote: > >> >> On Wed, 11 Jul 2018 21:29:09 -0700, tabbypurr wrote: > >> >> > On Thursday, 12 July 2018 04:43:31 UTC+1, Johnny B Good wrote: > >> >> >> On Wed, 11 Jul 2018 06:44:02 -0700, tabbypurr wrote: > >> >> >> > On Wednesday, 11 July 2018 02:20:36 UTC+1, Johnny B Good > >> >> >> > wrote:> >> That still doesn't really make a lot of sense. I looked at the fuel > >> consumption graph for bio-diesel and for the 1KW point on the graph it > >> equated to 0.64 litres per hour which is only slightly less than the > >> 0.68 litre per hour figure for the 670W output level of the PGI 1200 > >> B2. To be fair, that's an apples and oranges comparison but I don't > >> have a graph for the Parkside units. > >> > >> Alternatively, at the 700W level, the Listeroid graph shows a 0.15 US > >> gal per hour rate which equates to 0.57 litre per hour despite the > >> reduced efficiency of the consumption per KWH figure which flattens out > >> in the range 1250 to 2500 watts at a per KWH peak of 0.5 litre per KWH > >> of energy generated. When you look at the 500W figure that per KWH > >> consumption hits the 0.98 litre mark which is likely much higher than > >> the Parkside's consumption rate at this production level (500W load). > >> > >> If the generator spends most of its run time operating at the 300W > >> level, the litre per KWH rate gets even worse leaving the Parkside the > >> winner in this case but, of course, that neglects the much lower cost > >> per litre of duty free diesel over that of petroleum (gasoline). > >> > >> Also, the Listeroid graph is handicapped by the use of a conventional > >> single phase 230v alternator generator head and the extra losses of a > >> drive belt totally absent in the case of the direct drive PM three > >> phase alternator powered inverter suitcase generator. > >> > >> For anyone living off-grid, the choice of a large low revving diesel > >> prime mover to drive a generator head (whether it's a conventional > >> single phase 230v alternator or a geared up three phase PM alternator > >> with inverter module), is a no-brainer one. However, for someone > >> looking for an emergency backup generator to mitigate winter outages or > >> looking for a more luxurious wilderness trekking experience, the > >> lightweight suitcase inverter genset becomes the no-brainer option > >> (that 1KW Parkside unit only weighs in at a mere 13Kg!). > > > > Do you have links to the graphs & specs of the units you're comparing? > > The graph is on this page <http://www.utterpower.com/listeroi.htm>and it reveals what I suspected. It's common knowledge that diesel gens lose efficiency as load drops. Diesel gens are sized to match max load rather than spending much of their life under light load. It is no surprise that the fuel advantage falls away under very light load.> Just coincidentally, regarding the weight of the Parkside inverter > genset, I've just finished watching a documentary called "The Rise and > Fall of Nokia" where at the very end of the final credits, the weight of > a very early cell phone was quoted as being 13Kg! Its proud owner had > apparently carried it around whilst on a family day's outing at the zoo > and didn't receive a single call. > > Quite frankly, I was totally staggered by this statement having had to > carry the generator from the house into the back garden and then back > again, I know just how heavy a 13Kg genset (admittedly, with another > couple of Kgs worth of fuel and 200g of lube oil) is to carry one handed. > That guy must have had considerable upper body strength to tote such a > beast around for the best part of a day is all I can think. > > It's an unusually "Interesting Fact"(tm) I can now quote - that it only > weighs as much as an early generation mobile phone. :-)they were normally fitted to cars then. And he was lucky not to receive a call - the call costs were frightening. NT> >> >> >> However, they can be run on duty free diesel for about half the > >> >> >> cost of a petrol/gasoline generator. Indeed they're not fussy > >> >> >> about what fuel oil you choose to run them on so you have a lot > >> >> >> more fuelling options. > >> >> >> > >> >> >> Thank you for that sage advice. I do appreciate what you're > >> >> >> saying but > >> >> >> unfortunately, I'm not trying to live off grid and nor do I have > >> >> >> the space to install such venerable machinery. On top of which, > >> >> >> the standard generator heads typically fitted to these > >> >> >> listeroids[1] no longer suit the needs of modern day lighting and > >> >> >> computer loadings, particularly true in the case of my venerable > >> >> >> Smartups2000 with its 9.4μF's worth of capacitive loading across > >> >> >> its mains input which sends conventional single phase AVR > >> >> >> controlled 230vac 50Hz alternators into a massive over-volting > >> >> >> state as a result. > >> >> > > >> >> > not hard to add an inductive load to protect against capacitive > >> >> > loads > >> >> > >> >> Yeah, I used to think that too. :-( > >> >> > >> >> Believe me, that's exactly what I tried but it failed to remedy the > >> >> problem. > >> > > >> > Not enough inductive current I presume. > >> > >> Judging by the effect it had on my first Parkside genset, I'd say it > >> had > >> provided ample inductive current. I'd forgotten that I still had it in > >> circuit when I hooked up the first generator to the cable leading into > >> the basement to my Smartups2000 (not yet plugged into the business end > >> of that cable), so was surprised when the generator started labouring > >> when I plugged it in. > > > > > >> Unfortunately, it never occurred to me to verify the claimed overload > >> wattage calibration setting so I landed up with the one that signalled > >> this state at the 980W mark rather than the expected 1030 to 1050 watt > >> mark. > >> > >> I suppose it's just possible that the other could have been set > >> exactly > >> the same, possibly all of them, in which case I'd be left to consider a > >> calibration error on my test equipment being on the wrong side of the > >> +/-3% accuracy tolerance range (both my analogue and two digital > >> wattmeters being within 1% of each others' readings in the 1 to 1000W > >> range makes this unlikely though not impossible). > >> > >> If Lidl ever put these B2 models back on offer at the same 99 quid > >> price, I'll be snapping a couple of them up for testing. At that price, > >> it's well worth holding a spare in reserve anyway. > >> > >> Normally, with such miscalibration issues as this, I'd be adjusting > >> the > >> relevant trimmer. Unfortunately, the inverter module used is completely > >> devoid of any such trimmers - presumably they're preset in the factory > >> (possibly via a JTAG connector - there are a couple of unused header > >> blocks that could be candidates for this function). > > > > Likely no setting option other than by replacing a resistor. > > Yes, there is that rather annoying possibility. There may even be a set > of three or four trimpots on the encapsulated board hidden *beneath* the > surface rather than as in the case of the Workzone's inverter module (and > in photos I've seen of the PGI 1200 A1's inverter module and at least one > other inverter genset), where the trimpots poke up out of the > encapsulation compound specifically to allow post production adjustments. > > My only option to get around this little irritation may be to wait for > another batch of PGI 1200 B2s to go on sale at Lidl so I can swap in a > module that's been adjusted on the high side of the 1KW setting from a > donor set which I can return for refund. At just 99 quid, I'd quite like > to get hold of a spare as well, preferably one that's been set 2 or 3 > percent above the 1KW overload warning point rather than below. > > > > > > >> > with respect there are easier ways. I'm sorry if pointing that out > >> > upset you. > >> > >> Not annoyed, irritated? yes! but annoyed? no. > >> > >> Ok, suggest an 'easier way' then. > > > > I did, a wacking great inductor. Inductor i needs to exceed capacitive > > i. A pair of MOTs in series would be my first thought. > > > > I know you said it didn't work for you, but consider this. If inductive > > i exceeds capacitive i, the genny sees zero capacitive i. How then can > > it overvolt due to capacitance? IOW I suspect an unfound flaw in the > > implementation somewhere. > > > I reckon I'd need to shunt the line with a 250mH inductor but creating a > 240vac rated 250mH inductor is a lot harder than you might think! I only > managed to create a half Henry's worth of inductance which I'd hoped > would be enough to mitigate the problem but it didn't quite cut it (I'd > run out of 360VA mains transformer primaries by then). > > Even so, it must have created a 4 or 5 amp 90 degree lagging current > load going by the response of that first PGI 1200 B2 to my forgetting to > disconnect it from the circuit. Anyway, that major problem is ancient > history now, thank Ghod! I can now concentrate on a new project, how to > not let a perfectly good BLDC starter motor, currently employed only as a > high voltage three phase alternator, go to waste. :-) > > -- > Johnny B Good
Reply by ●July 14, 20182018-07-14
On Fri, 13 Jul 2018 23:21:45 -0700, tabbypurr wrote:> On Saturday, 14 July 2018 02:25:43 UTC+1, Johnny B Good wrote: >> On Fri, 13 Jul 2018 15:55:27 -0700, tabbypurr wrote: >> > On Friday, 13 July 2018 15:28:27 UTC+1, Johnny B Good wrote: >> >> On Thu, 12 Jul 2018 17:43:20 -0700, tabbypurr wrote: >> >> > On Thursday, 12 July 2018 19:43:48 UTC+1, Johnny B Good wrote: >> >> >> On Wed, 11 Jul 2018 21:29:09 -0700, tabbypurr wrote: >> >> >> > On Thursday, 12 July 2018 04:43:31 UTC+1, Johnny B Good wrote: >> >> >> >> On Wed, 11 Jul 2018 06:44:02 -0700, tabbypurr wrote: >> >> >> >> > On Wednesday, 11 July 2018 02:20:36 UTC+1, Johnny B Good >> >> >> >> > wrote: > >> >> That still doesn't really make a lot of sense. I looked at the fuel >> >> consumption graph for bio-diesel and for the 1KW point on the graph >> >> it equated to 0.64 litres per hour which is only slightly less than >> >> the 0.68 litre per hour figure for the 670W output level of the PGI >> >> 1200 B2. To be fair, that's an apples and oranges comparison but I >> >> don't have a graph for the Parkside units. >> >> >> >> Alternatively, at the 700W level, the Listeroid graph shows a 0.15 >> >> US >> >> gal per hour rate which equates to 0.57 litre per hour despite the >> >> reduced efficiency of the consumption per KWH figure which flattens >> >> out in the range 1250 to 2500 watts at a per KWH peak of 0.5 litre >> >> per KWH of energy generated. When you look at the 500W figure that >> >> per KWH consumption hits the 0.98 litre mark which is likely much >> >> higher than the Parkside's consumption rate at this production level >> >> (500W load). >> >> >> >> If the generator spends most of its run time operating at the 300W >> >> level, the litre per KWH rate gets even worse leaving the Parkside >> >> the winner in this case but, of course, that neglects the much lower >> >> cost per litre of duty free diesel over that of petroleum >> >> (gasoline). >> >> >> >> Also, the Listeroid graph is handicapped by the use of a >> >> conventional >> >> single phase 230v alternator generator head and the extra losses of >> >> a drive belt totally absent in the case of the direct drive PM three >> >> phase alternator powered inverter suitcase generator. >> >> >> >> For anyone living off-grid, the choice of a large low revving >> >> diesel >> >> prime mover to drive a generator head (whether it's a conventional >> >> single phase 230v alternator or a geared up three phase PM >> >> alternator with inverter module), is a no-brainer one. However, for >> >> someone looking for an emergency backup generator to mitigate winter >> >> outages or looking for a more luxurious wilderness trekking >> >> experience, the lightweight suitcase inverter genset becomes the >> >> no-brainer option (that 1KW Parkside unit only weighs in at a mere >> >> 13Kg!). >> > >> > Do you have links to the graphs & specs of the units you're >> > comparing? >> >> The graph is on this page <http://www.utterpower.com/listeroi.htm> > > and it reveals what I suspected. It's common knowledge that diesel gens > lose efficiency as load drops. Diesel gens are sized to match max load > rather than spending much of their life under light load. It is no > surprise that the fuel advantage falls away under very light load. >That graph revealed just what I *expected*. For anyone who's familiar with the "ICE 101" course materials, they wouldn't have been at all surprised by that graph which applies to pretty well all types of ICE, not just diesel engines. With some obvious differences, it's more or less the same type of graph you'd see for a petrol (gasoline) engined generator setup. The difference, when you're comparing diesel and petrol engine prime movers both sized for best efficiency at the same generator output level is that the diesel engine offers about twice the fuel efficiency of the petrol engine setup. I've just calculated the swept volume as being 1.433 litres. You'd probably need to specify a 2 litre 4 cylinder car engine tuned to operate at 800rpm or so to get almost (but not quite) the same fuel efficiency. Spreading the swept volume across 4 cylinders increases the frictional losses in the cylinders and the additional valve train gear. Modern materials and bearing types will mitigate this to some extent but the Listeroid's utter simplicity and minimised frictional losses are what makes this such an appealing alternative to a modern "Lightweight" 'de- tuned' four cylinder diesel engine bought dead cheap at a local car breaker's yard.> >> Just coincidentally, regarding the weight of the Parkside inverter >> genset, I've just finished watching a documentary called "The Rise and >> Fall of Nokia" where at the very end of the final credits, the weight >> of a very early cell phone was quoted as being 13Kg! Its proud owner >> had apparently carried it around whilst on a family day's outing at the >> zoo and didn't receive a single call. >> >> Quite frankly, I was totally staggered by this statement having had to >> carry the generator from the house into the back garden and then back >> again, I know just how heavy a 13Kg genset (admittedly, with another >> couple of Kgs worth of fuel and 200g of lube oil) is to carry one >> handed. >> That guy must have had considerable upper body strength to tote such a >> beast around for the best part of a day is all I can think. >> >> It's an unusually "Interesting Fact"(tm) I can now quote - that it >> only >> weighs as much as an early generation mobile phone. :-) > > they were normally fitted to cars then.They were portable rather than mobile, rather in the same way as the Osbourne One portable PC and Akai's famous M8 stereo tape recorder (a mere 47 Lbs) had been classified in the "Portable" category only by virtue of having a hard cover and a sturdy carrying handle. :-)> > And he was lucky not to receive a call - the call costs were > frightening.If he could afford such an innovative and novel product (well paid Nokia employee or not), the cost of an incoming call would have been the least of his concerns! :-) Getting back on topic (this isn't a private discussion :-) ), I've just had a conversation with my Son in Law who's into the R/C helicopter and drone flying scene. It turns out that he's awaiting the arrival of some 30A 2-4S R/C brushless ESC modules from Bangood to upgrade the 20A ones he's currently got fitted in his drone. It looks like I'll be able to borrow a 16.8v rated 20A R/C brushless ESC module in a few weeks time once his order finally arrives and I'll finally be able to get some test data at long last! I'll only be testing at a basic level with the ignition disabled and, initially with the spark plug removed, just to see what sort of cranking speed, if any, can be obtained at this low voltage level. I think I'll be requiring a starting battery voltage of at least 24 volt in order to stand any chance at all of actually being able to start the engine. Testing with only a 12v SLA[1] should be sufficient to validate the concept and give me some data from which to extrapolate a more accurate estimate of the BLDCM drive voltage requirement. I now plan on using a 400v rated BLDC motor controller (with 600v rated IGBTs) in the finalised circuit to eliminate the fast isolator relay that would otherwise be needed to protect a low voltage BLDC motor controller. I'll still need to protect the starter circuit from the alternator's 300vac output voltage once it's up to speed but a simple 10A 800PIV rated anti-backfeed diode should nicely serve the purpose in this usage case. Having measured the actual alternator coil resistances this afternoon (8.5Ω phase to phase as opposed to my initial guestimate of an ohm or so), it's beginning to look like even 48v may not be quite high enough for the task. Until I actually generate some test data, I can only speculate about the actual voltage requirements at this stage. [1] I might even be able to borrow a 4S LiPo battery pack and charger as well as that 20A ESC module (along with whatever else may be needed to control the module). -- Johnny B Good
Reply by ●July 14, 20182018-07-14
On Sunday, 15 July 2018 00:27:49 UTC+1, Johnny B Good wrote:> On Fri, 13 Jul 2018 23:21:45 -0700, tabbypurr wrote: > > On Saturday, 14 July 2018 02:25:43 UTC+1, Johnny B Good wrote:> >> Just coincidentally, regarding the weight of the Parkside inverter > >> genset, I've just finished watching a documentary called "The Rise and > >> Fall of Nokia" where at the very end of the final credits, the weight > >> of a very early cell phone was quoted as being 13Kg! Its proud owner > >> had apparently carried it around whilst on a family day's outing at the > >> zoo and didn't receive a single call. > >> > >> Quite frankly, I was totally staggered by this statement having had to > >> carry the generator from the house into the back garden and then back > >> again, I know just how heavy a 13Kg genset (admittedly, with another > >> couple of Kgs worth of fuel and 200g of lube oil) is to carry one > >> handed. > >> That guy must have had considerable upper body strength to tote such a > >> beast around for the best part of a day is all I can think. > >> > >> It's an unusually "Interesting Fact"(tm) I can now quote - that it > >> only > >> weighs as much as an early generation mobile phone. :-) > > > > they were normally fitted to cars then. > > They were portable rather than mobile, rather in the same way as the > Osbourne One portable PC and Akai's famous M8 stereo tape recorder (a > mere 47 Lbs) had been classified in the "Portable" category only by > virtue of having a hard cover and a sturdy carrying handle. :-) > > > > > And he was lucky not to receive a call - the call costs were > > frightening. > > If he could afford such an innovative and novel product (well paid Nokia > employee or not), the cost of an incoming call would have been the least > of his concerns! :-)no, calls really were frighteningly expensive. No-one used the things unless they really needed to, so a call while at the zoo would not be expected. NT
Reply by ●July 15, 20182018-07-15
On Fri, 13 Jul 2018 04:21:54 +0000, Johnny B Good wrote:> On Thu, 12 Jul 2018 14:54:12 -0700, Lasse Langwadt Christensen wrote: > >> torsdag den 12. juli 2018 kl. 23.10.05 UTC+2 skrev Johnny B Good: > > ====snip==== > >>> It's a pity I hadn't framed my question that succinctly in the first >>> place but it's only after receiving so much advice on every >>> alternative but the one I'm after (all of which I'd already considered >>> and discounted) that the need to restate my question becomes apparent. >>> Not to put too fine a point on it, the question I'm really asking is >>> this:- >>> >>> "What is the best way to drive the 350v three phase PM alternator in >>> my >>> inverter genset as a BLDC starter motor?" >>> >>> I can understand why such alternatives were being offered. A lot of >>> similar pleas for help often involve needlessly complex electronic >>> solutions to problems that can often be better addressed more >>> pragmatically using a low tech option. Believe me, the complexity of a >>> BLDC motor controller *is* the most pragmatic solution in this case. >>> :-) >>> >>> >> some kind of BLDC controller, sensored using three HALL elements rather >> than sensorless is probably preferable with the low speed and uneven >> load from the engine > > I'm only too aware of the problem that can result when a sensorless > BLDC > controller has to fight compression resistance without any run up to > recruit the flywheel inertia to assist pulling through this part of the > engine cycle. > > However, I'd like to avoid modifying the alternator with add on sensors > if possible. One technique that comes to mind is to detect the lack of > acceleration to determine that the engine is at the start of the > compression stroke and to use this to reverse the direction of the motor > until it detects the 'previous' compression stroke whereupon it switches > back to forward, using the compression to help bounce it into forward > acceleration so that there is sufficient inertial energy built up in the > flywheel to push through the next and subsequent compression strokes > until the engine either fires up or the start sequence times out. > > >> 3x half-bridge drivers that can handle the starting current and the >> voltage of the generator running, something like this might work >> https://www.digikey.com/product-detail/en/sanken/SCM1243MF/SCM1243MF- > ND/4454409 > > I've been studying the product info on that family of driver chips, in > particular the SCM1246MF which looks the most promising with its 400v > Vbb rating and the IGBT max voltage ratings of 600v and a 30A drive > rating. I'm planning on using a 24v starter battery for my initial tests > so the Vsat figure of 1.7v at 30A isn't a major problem especially as > the phase winding resistance is likely to be around an ohm (yet to be > tested) so max starting current (hence torque) from standstill will > likely be limited to around the 20A mark (about four times the normal > maximum 30 seconds output current limit as an alternator). >Well, it seems my 'guessed 1 ohm or so windings resistance figure' was way off the mark. When I finally got round to lifting the lid off the genset to take some resistance measurements, I was quite surprised to discover a phase to phase resistance value of 8.5Ω! Making the reasonable assumption that the alternator stator is wired in star (Wye) configuration, that's a phase coil resistance value of 4.25Ω. Be that as it may, when effectively operating as a 400v DC generator using the 6 diode bridge and 450vdc rated 330μF smoothing capacitor[1] in the inverter module, the required *averaged* current to supply a 97% efficient inverter module generating 1KW of 230vac at 50Hz from a 400vdc supply approximates to 2.6 amps (for the 30 seconds overload maximum of 1.2KW, it approximates to 3.1 amps). For a DC generator based on the fullwave rectified output of a three phase alternator, this a close enough approximation to a 400vdc supply of 8.5Ω impedance to estimate the losses in the generator windings at around the 58 and 82 watt mark respectively. This suggests efficiencies of 94 to 92 percent for the 1000 and 1200 watt inverter output levels which seem not unreasonable values for a small machine. As a BLDC motor I can consider a stalled torque current value of 6A maximum and a cranking current demand of 2.5 to 3 amp as a reasonable first guess at requirements from the controller. Until I finally get to run some actual tests, I could be wildly over or underestimating these requirements. Hopefully, the loan of a 20A 16.8v rated R/C brushless ESC module from my son in law in a fortnight or so's time should let me know one way or the other. The only thing that keeps my attention on this project is that it might turn out to be ridiculously easy to utilise the PM alternator as a starter motor or it'll need a clever BLDC "starter motor algorithm" programmed into its controller to overcome the compression resistance problem by, so to speak, a surprise attack from the rear. Although I'm not lacking in imagination regarding ways and means of getting this to work, my problem right now is a total lack of 'Expertise'. Once I've gained some actual experience, I should be able to figure out a way to utilise the built in BLDC motor currently disguised as just a three phase PM alternator if not as a self sufficient starter motor solution then at the very least, a means of electrical assistance to the recoil pull starter by programming the controller's microprocessor to detect the initial rotation imparted by the pull cord to initiate the motor drive routine and to detect when the engine has fired up and reset itself back to standby mode. In this case the user simply has to find the compression point with ignition switched off and pull it just past that point before switching the ignition back on to give one good yank on the cord to let the BLDC module take over to do the hard work until the engine fires up or the start algorithm times out. I could simplify the assisted pull start routine by getting the module to inhibit the ignition until after it has kicked in (I could tap into the low oil level warning/protection signal line to inhibit the ignition module to achieve this anti-kickback effect). Actually, now that I've considered it, this would be a useful modification to have in the first place with the current pull start system. I'm surprised it isn't already a feature of the inverter module. The only problem with a separate add-on circuit is in dealing with the issue of safely sampling the waveform from the alternator to count a long enough train of pulses above a threshold frequency to indicate that the user has managed to build up sufficient momentum to go through the next compression cycle without risk of kickback and re-enable the ignition module accordingly. There is a seperate low voltage single phase winding (0.4Ω) on the alternator obviously intended to power the classic 8.3A 12v battery charging port usually provided on small gensets. Parkside, in their infinite cost cutting wizdumb, decided not to fit the required panel socket and wiring to the inverter module's battery charging rectifier connection port. If this battery charging port isn't cursed by an unnecessary smoothing capacitor, the unsmoothed rectifier pulses would provide a safe source of pulses by which to effect an anti-kickback circuit. However, I'll worry about that as a fallback project should I be forced to give up on my electric starter project. [1] This relates more to the 5 or 6 KHz sampling frequency ripple current load from the H bridged Class D amp inverter than it does to the 1350 or so Hz rectified ripple component in the 400vdc supply. -- Johnny B Good
Reply by ●July 16, 20182018-07-16
On 2018-07-16, Johnny B Good <johnny-b-good@invalid.ntlworld.com> wrote:> Well, it seems my 'guessed 1 ohm or so windings resistance figure' was > way off the mark. When I finally got round to lifting the lid off the > genset to take some resistance measurements, I was quite surprised to > discover a phase to phase resistance value of 8.5Ω! Making the reasonable > assumption that the alternator stator is wired in star (Wye) > configuration, that's a phase coil resistance value of 4.25Ω.If you remove the spark plug and energise the windings with say 1A DC you can get a feel for how much rope-force that's equivalent to and compare that with how much rope force is needed for the compression stroke. that should allow you to estimate how much run current it'll take to strart the thing using the generator. -- ت
Reply by ●July 17, 20182018-07-17
On Mon, 16 Jul 2018 20:29:23 +0000, Jasen Betts wrote:> On 2018-07-16, Johnny B Good <johnny-b-good@invalid.ntlworld.com> wrote: > >> Well, it seems my 'guessed 1 ohm or so windings resistance figure' was >> way off the mark. When I finally got round to lifting the lid off the >> genset to take some resistance measurements, I was quite surprised to >> discover a phase to phase resistance value of 8.5Ω! Making the >> reasonable assumption that the alternator stator is wired in star (Wye) >> configuration, that's a phase coil resistance value of 4.25Ω. > > If you remove the spark plug and energise the windings with say 1A DC > you can get a feel for how much rope-force that's equivalent to and > compare that with how much rope force is needed for the compression > stroke. that should allow you to estimate how much run current it'll > take to strart the thing using the generator.Thanks Jasen. Funnily enough, that thought *had* crossed my mind at some point in my pondering this 'Great Unknown'. :-) Now that I've actually *measured* the phase to phase winding resistance (all three measuring 8.5Ω - 8.6Ω minus the 0,1Ω test lead resistance), I can try this test for the 1.5A value by simply connecting a 12v SLA across two of the phases. My thought (and I presume yours too) is that it'll lock the rotor into the nearest 'cogging point', allowing me to get a feel for or even measure how much pull is needed to drag it out of lock. Obviously, I'd want to rotate the crankshaft to the point of least resistance from the camshaft which happens to be when both valves are shut. This of course, is when the engine is on its compression/power stroke. Removing the spark plug in this case is vital to minimising the loading to just the minimum of frictional forces to get a sense (whether measured or by 'feel') of the net torque available from circa 1.5A of drive current. Taking a closer look at the pull cord mechanism, the rope unwinding diameter seems to start off at about 6 to 7 cm, reducing as the rope is (rapidly, one hopes!) unwound. This seems a remarkably high gearing ratio, requiring a lot of rope tension to achieve the required starting torque. With regard to the 'pull' required at the outer rotor/flywheel of the alternator to achieve the same torque figure, this looks to have about a 3:1 advantage from its circa 20cm rotor diameter. However, that of course means it'll need three times the driving voltage to attain the required cranking speed which, in view of the surprisingly high winding resistance [2], is less likely to be a mere 24v and more likely a 48 to 60vdc requirement. Of course, given a reasonable level of fitness and upper body strength (and cunning[1]), this high gearing ratio (which neatly gets even higher as the rope is unwound) has obviously been chosen as an optimised match to the dynamics of 'throwing a spear with the aid of a throwing stick' technique which extends the hand's reach to multiply the velocity being imparted to a spear that's just a fraction of the mass of the hand and forearm to improve kinetic energy transfer from the arm muscles into said spear (in this case, the cranking of a single cylinder 4 stroke engine with sufficient speed to start it up). The problem of course is that you need to be reasonably fit with, given the lack of a fuel priming bulb or automatic decompression release mechanism, a minimum level of stamina to boot. In my case, fitness and stamina are best described as being on the 'marginal side', hence my interest in taking advantage of what I'm pretty certain is a 'built in BLDC starter motor' by the trivial matter of connecting a small electronic module and battery with no mechanical modifications whatsoever. I'll report back as soon as I've tried this test. ======================================================================== NOTES: [1] You need to feel for the compression point and drag through it just far enough to avoid its impact (a complete stalling of your efforts and often, most horrible of all, a nasty 'Kickback') so as to give you the required run up to build sufficient kinetic energy in the flywheel (PM alternator rotor) to assist your efforts in rapidly completing the next suck, squeeze, bang part of the cycle - a successful 'bang' will take of the 'blow' part and all subsequent 'blow's. :-) [2] My gut feeling about the actual measured resistance of the stator windings being unexpectedly higher than my initial guestimate has been somewhat validated by the published values for the alternator used by the Powerhouse PH2700PRi 2.6KW cont. rated inverter genset where they quote phase to phase values of just 0.250 to 0.350Ω. Since this is to power a 120v inverter module of just under three times the power rating of the Parkside unit, you need to multiply by a factor of four to account for the doubling up of voltage required for a 240v version and then by 2.6 to account for the lower power output of a 1000W cont. versus the 2600W cont. of the Powerhouse example. This gives a suggested value of resistance around the 2.6 to 3.64 ohms mark, a median of 3.12Ω which makes the Parkside alternator winding resistance values some 2.7 times higher than expected by extrapolation from the Workhorse example. Even so, this would still have been about twice what I'd initially guestimated before I'd clapped eyes on the Powerhouse data. Comparing the values given for the DC charging winding (Blue-Blue in a seperate connector) in the Powerhorse manual of 0.045-0.070 Ω versus the 0.4Ω measurement of the Blue-Blue wires in the 6 station connector used for the phase winding connections in the Parkside unit, I'm beginning to wonder whether this dichotomy is the result of Powerhouse utilising Neodymium magnets where Parkside have settled for the old fashioned cobalt nickel cheapies. Incidentally, what takes the place of the blue battery charging connections in the Parkside connector, is shown in the Powerhouse diagram as being a "Sub winding", white wires with a resistance value of 0.100-0.160 Ω. Presumably, if such a sub winding exists in the Parkside unit (I don't have a diagram to check this out and it's hard to sort out from the mass of wires visible between the inverter module and the engine/ generator assembly just what else may be wired into the alternator stator plate), it's presumably wired to its own seperate 2 pin connector hidden somewhere in the wiring harness. One can only guess the purpose of this "Sub winding" in the case of the Powerhorse since the ignition coil seems to be a magneto coil powered from a magnet (flanked by similar sized lumps of soft iron) all riveted to the outside of the flywheel rotor (with a larger chunk of iron riveted onto the opposite side as a counterbalance). It clearly isn't anything to do with powering an electronic ignition module as might be the case with the Parkside unit, so whatever its purpose (it connects to the inverter module via a flylead connected 6 pin male connector in the Powerhorse in place of the blue DC generator connections in the parkside's embedded 6 pin male connector), it remains a mystery. In the case of the Parkside, there may well be a similar "Sub winding" which could well be providing power to the electronic ignition module for all I know. However, what I do know is that the Powerhorse has split the blue DC battery charging coil connections off to feed a totally seperate from the inverter DC generator module for battery charging, including its own starter battery. Whilst, otoh, this function appears to have been integrated into the inverter module used in the Parkside unit which appears to have not been wired up to a battery charging socket and hence an unused feature which might ultimately prove useful if I do succeed in my electric starter project as the means to keep the starter battery charged up - not necessarily a 12v LA (flooded cell, GM or Gel type). I can keep my starter battery options open on that one in view of the availability of commodity DC-DC converter and battery management modules. A long life Li-ion battery ime, might prove a less troublesome option. :-) -- Johnny B Good
Reply by ●July 17, 20182018-07-17
On Tue, 17 Jul 2018 15:37:08 +0000, Johnny B Good wrote:> On Mon, 16 Jul 2018 20:29:23 +0000, Jasen Betts wrote: > >> On 2018-07-16, Johnny B Good <johnny-b-good@invalid.ntlworld.com> >> wrote: >> >>> Well, it seems my 'guessed 1 ohm or so windings resistance figure' >>> was >>> way off the mark. When I finally got round to lifting the lid off the >>> genset to take some resistance measurements, I was quite surprised to >>> discover a phase to phase resistance value of 8.5Ω! Making the >>> reasonable assumption that the alternator stator is wired in star >>> (Wye) >>> configuration, that's a phase coil resistance value of 4.25Ω. >> >> If you remove the spark plug and energise the windings with say 1A DC >> you can get a feel for how much rope-force that's equivalent to and >> compare that with how much rope force is needed for the compression >> stroke. that should allow you to estimate how much run current it'll >> take to strart the thing using the generator. > > Thanks Jasen. > > Funnily enough, that thought *had* crossed my mind at some point in my > pondering this 'Great Unknown'. :-) > > Now that I've actually *measured* the phase to phase winding resistance > (all three measuring 8.5Ω - 8.6Ω minus the 0,1Ω test lead resistance), I > can try this test for the 1.5A value by simply connecting a 12v SLA > across two of the phases. >====snip===> > I'll report back as soon as I've tried this test. >Well, the results were encouraging enough to make me think this project might be even easier to accomplish than I had envisioned. I'm now looking to concocting some sort of manually operated commutating switch to get an even better feel for just how well the alternator might perform as a BLDC starter motor (I've just got to take another look at the basic principles to refresh myself of the details). Also, it has crossed my mind that I might be better off designing a custom BLDC motor drive circuit that bypassess the need for a seperate 12 to 48 to 60 volt dc-dc converter with a mains voltage rated BLDC driver module. -- Johnny B Good
