On Tue, 4 Sep 2018 15:21:54 -0700 (PDT), tabbypurr@gmail.com wrote:>On Tuesday, 4 September 2018 18:51:31 UTC+1, John Larkin wrote: >> On Tue, 4 Sep 2018 09:40:37 -0700, John Robertson <spam@flippers.com> >> wrote: >> >> >On 2018/09/04 9:34 AM, John Larkin wrote: >> >> On Tue, 4 Sep 2018 09:30:04 -0700, John Robertson <spam@flippers.com> >> >> wrote: >> >> >> >>> On 2018/09/03 7:55 AM, John Larkin wrote: >> >>>> On 3 Sep 2018 05:15:10 -0700, Winfield Hill <hill@rowland.harvard.edu> >> >>>> wrote: >> >>>> >> >>>>> <698839253X6D445TD@nospam.org> wrote... >> >>>>>> >> >>>>>> And do not forget the 12V DC motor driving a 350V DC generator solution :-) >> >>>> >> >>>> Dynamotor. For regulation, control the field of the generator. I think >> >>>> that's an amplidyne or something. They used them for things like >> >>>> aiming the guns on battleships. >> >>>> >> >>>>> >> >>>>> 100 relays switching 100 Li-ion cells from parallel to series. >> >>>> >> >>>> Overkill. Two banks of 30 relays each should do it. >> >>>> >> >>>> >> >>> >> >>> Overkill. Use 4PDT 12VDC relays and I think you are down to around 50 >> >>> relays...(2 batteries/relay). >> >>> >> >>> John >> >> >> >> There is my relay version of the Cockcroft?alton multiplier that Phil >> >> calls the Groucho Marx Generator. >> >> >> >> >> > >> >I'd like to see that schematic! I work on both EM and SS equipment and >> >so enjoy all forms of electrical abuse... >> > >> >John :-#)# >> >> My mistake. It was Harpo. >> >> https://www.dropbox.com/s/qycxyrty0hkkzo1/Harpo_Marx.JPG?raw=1 >> >> I wonder if there is a variant that doesn't apply so much voltage to >> the relay contacts. >> >> How about a rotating cam that drives a lot of switch contacts? Or a >> rotating insulated shaft that drives a lot of generators (stepper >> motors would work) wired in series. >> >> I'd like to get a bunch of doorknob capacitors, charge them each to >> 30KV, and then stack or drop them inside a plexiglass tube. > >I've got it. Charge each doorknob to 30kV then fire it into the top of the plastic tube with a toy cannon. Rotating contacts top & bottom extract the output from the pile of Cs, while they're let out at the bottom at the same rate as they're fired into the top. > > >NTNothing so fancy. I figured that I could just charge them and drop them into the tube. When the tube is full, it could be ballpark a megavolt between the ends. -- John Larkin Highland Technology, Inc trk jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Very high gain transformerless boost converter - is it possible
Started by ●September 2, 2018
Reply by ●September 4, 20182018-09-04
Reply by ●September 5, 20182018-09-05
<bill.sloman@ieee.org> wrote in message news:e5382b49-b76b-4e28-a42c-1c6ba8cf00a1@googlegroups.com...>> I still feel sorry for mechanical engineers who have no decent >> equivalent to a switching regulator. > > It's called a gearbox. Not suitable for gramophone speed regulation, but > belt drive turntables offer other approaches (not that any of them would > be a sensible choice in real life). >That'd be a transformer. CVT is the best they've got, but it's a variac, and like a variac, suffers from losses where the brushes short across turns, and wear. Here's a project that tried: https://web.wpi.edu/Pubs/E-project/Available/E-project-042711-231644/unrestricted/Switch-Mode_CVT_Torsion_Spring.pdf It's a shame that no material has an extremely high speed of sound. Beryllium is the highest by far among metals, topped only by diamond (maybe). That's not very encouraging for an application that's expecting high impact and abrasion forces... I would suspect a hydraulically actuated resonant converter might not be too terrible, but it would be a pain to design, even worse of a pain to dampen properly (to keep it from shaking the car apart, let alone be quiet enough for the passengers), on account of the many more vibrational degrees of freedom mechanical parts have, compared to electrical circuits; and it still wouldn't get anywhere near the power density of an electric converter of the same rating. Tim -- Seven Transistor Labs, LLC Electrical Engineering Consultation and Design Website: https://www.seventransistorlabs.com/
Reply by ●September 5, 20182018-09-05
tabbypurr wrote>> Mechanical, centrifugal speed control, Edison already used it. >> No losses. >> >> I had a record player that used that >> https://en.wikipedia.org/wiki/Centrifugal_governor > >That was used long before Edison. > >You say no losses. How would you implement it in a lossless way in this case?Ferry Zimple We call that a 'variomatic', wheels with varying diameter, also seen in dome desktop electric drills, first here used in the DAF automobile transmission: https://en.wikipedia.org/wiki/Variomatic The centrifugal governor controls the CVT and thus the speed of the generator, while the electric motor is running at approx. the same speed. The load on the motor changes and is reduced for a lower transmission ratio, and so does the power consumption.
Reply by ●September 5, 20182018-09-05
jurb6006 wrote>>"I think the record player speed regulator was frictional hence lossy. " > >Yes but against a spring that's wound up that is exactly what is needed. Electric motor not so much...It had an electric motor though, and a lever that moved the pushing plate fricton plate if you want) from the governer, so you could also move it to 45 rpm Made by Philips. IIRC it had worm drive from the motor to the turntable... Cannot find a picture of it online. Had great fun with it, learned a lot from it.
Reply by ●September 5, 20182018-09-05
On 2018-09-04, John Larkin <jjlarkin@highlandtechnology.com> wrote:> On Tue, 4 Sep 2018 13:56:38 -0700 (PDT), jurb6006@gmail.com wrote: > >>>"I think the record player speed regulator was frictional hence lossy. " >> >>Yes but against a spring that's wound up that is exactly what is needed. Electric motor not so much... > > I could imagine a nearly lossless regulator for a wind-up Victrola, > but not with 1930's technology.build a constant-speed flywheel that's going to require some tricky levers, but the right force to distance curve should allow you to construct a flywheel with masses that move radially that has near constant speed over a range of angular momentums. this could perhaps be could be a horizontal flywheel that has steel balls balls thay roll up inclined tracks by "centrifugal force" Then sense the position of the masses (perhaps use magnets) and have that turn the (spring) motor on and off. -- ت
Reply by ●September 5, 20182018-09-05
On Tuesday, September 4, 2018 at 6:29:48 PM UTC-7, John Larkin wrote:> I still feel sorry for mechanical engineers who have no decent > equivalent to a switching regulator.Well, not one that fits in the palm of the hand, but automatic transmissions are not unknown. I've got a couple of 'em parked outside.
Reply by ●September 5, 20182018-09-05
On Tuesday, September 4, 2018 at 3:19:29 PM UTC-7, tabb...@gmail.com wrote:> On Tuesday, 4 September 2018 17:35:41 UTC+1, John Larkin wrote: > > On Mon, 3 Sep 2018 21:51:17 -0700 (PDT), whit3rd <whit3rd@gmail.com> > > wrote:> > >Yes, an electric motor and a rubber band is the basis of many a > > >van de Graaff generator, but it's easier to get 350 kV than it > > >is to get 350W that way. That's REAL high voltage gain. > > > > What's the wall-plug efficiency of a Van de Graaff? > > I'm sure it's zero, +/- not very much.The modern equivalent (pelletron) claims <http://www.pelletron.com/products/pelletron-charging-chains/> circa 100 uA and 25MV capability: that's about four horsepower, and I'd guess the friction losses in the link-chain are very low indeed. The whole system is basically a motor, cogwheel, chain, and idler wheel at HV.
Reply by ●September 5, 20182018-09-05
On Wednesday, 5 September 2018 05:00:43 UTC+1, 69883925...@nospam.org wrote:> tabbypurr wrote> >> Mechanical, centrifugal speed control, Edison already used it. > >> No losses. > >> > >> I had a record player that used that > >> https://en.wikipedia.org/wiki/Centrifugal_governor > > > >That was used long before Edison. > > > >You say no losses. How would you implement it in a lossless way in this case? > > Ferry Zimple > > We call that a 'variomatic', > wheels with varying diameter, also seen in dome desktop electric drills, > first here used in the DAF automobile transmission: > https://en.wikipedia.org/wiki/Variomatic > > The centrifugal governor controls the CVT and thus the speed of the generator, > while the electric motor is running at approx. the same speed. > The load on the motor changes and is reduced for a lower transmission ratio, > and so does the power consumption.The variomatic was a rather interesting concept. The DAFs could really have done with computer control, vacuum control was far from ideal. And the cars so needed a restyle! NT
Reply by ●September 5, 20182018-09-05
Lasse Langwadt Christensen <langwadt@fonz.dk> wrote in news:c0d2cac5- e352-44cb-aa74-62536a50976f@googlegroups.com:> tirsdag den 4. september 2018 kl. 00.23.05 UTC+2 skrev Winfield Hill: >> jurb6006@gmail.com wrote... >> > >> > The best bet would be Dickson triplers stacked.=20 >> >> Do you have a few good references for the Dickson >> voltage multipliers? I only found two recent >> locked Academic papers (used my Harvard access to >> get them). No mention of why called Dickson, no >> paper by him, etc. Looks like Cockcroft-Walton. >> > > https://en.wikipedia.org/wiki/Voltage_multiplier#Dickson_charge_pump > > ;) > > >Thanks. Nice, descriptive article(s).
Reply by ●September 5, 20182018-09-05
On Tuesday, September 4, 2018 at 10:19:28 PM UTC-4, tabb...@gmail.com wrote:> On Wednesday, 5 September 2018 01:09:41 UTC+1, George Herold wrote: > > On Tuesday, September 4, 2018 at 6:19:29 PM UTC-4, tabby wrote: > > > On Tuesday, 4 September 2018 17:35:41 UTC+1, John Larkin wrote: > > > > On Mon, 3 Sep 2018 21:51:17 -0700 (PDT), whit3rd <whit3rd@gmail.com> > > > > wrote: > > > > >On Monday, September 3, 2018 at 1:07:08 AM UTC-7, 69883925...@nospam.org wrote: > > > > > > > > > >> And do not forget the 12V DC motor driving a 350V DC generator solution :-) > > > > > > > > > >Yes, an electric motor and a rubber band is the basis of many a > > > > >van de Graaff generator, but it's easier to get 350 kV than it > > > > >is to get 350W that way. That's REAL high voltage gain. > > > > > > > > What's the wall-plug efficiency of a Van de Graaff? > > > > > > I'm sure it's zero, +/- not very much. > > > > > > > > > NT > > > > Huh, I have no idea, but I'd bet (a beverage) it's better than 1%. > > > > George H. > > I took data at an FEL that used a big ass Van de Graff to > > accelerate the electrons. > > If I were really going to place a bet I'd take you on. I daresay there's a fair difference between the latest higher-tech van de graaf and something from their heyday. >Right, (I figure I owe most people here a six pack of 'beverages' already so another hardly matters.) But I was thinking of a lower cost 'toy' Van der Graff, like is used in physics demo's. I could ask some of the physics 'lab guys' to try and measure one. Heck, someone might have already done it. George H.> > NT
