On 30/06/2023 05:23, Ricky wrote:> On Thursday, June 29, 2023 at 6:57:22 PM UTC-4, Eddy Lee wrote: >> On Thursday, June 29, 2023 at 3:47:03 PM UTC-7, Ricky wrote: >>> On Thursday, June 29, 2023 at 6:37:31 PM UTC-4, TTman wrote: >>>> As part of an experiment with solar, I want to drive my 220V 3kW >>>> immersion heater with a suitable diode so that the effective power is >>>> ~1.5kW and can be driven by a smart switch so that it doesn't suck too >>>> much out of the 9.5kWh battery or solar panels.. What diode? This is UK >>>> spec. >>> You can do that, or... you can string two heaters in series. Doubling the resistance will cut the power in half. >> Power by half of half. > > As usual, you fail to understand. > > P = E^2 / R > > If you string two heaters in series, you have the same voltage, but twice the resistance, so half the power. >No, you don't understand this english stuff. Twin heaters are rare in the UK -- This email has been checked for viruses by Avast antivirus software. www.avast.com
half wave rectifier
Started by ●June 29, 2023
Reply by ●June 30, 20232023-06-30
Reply by ●June 30, 20232023-06-30
On 30/06/2023 09:02, Phil Allison wrote:> Arie de Muijnck wrote: > ---------------------------------- >>>> >>>> Anyway, this diode should work and I am using it for full bridge rectifier to pull maximum power out of my 220V inverter. >>>> >>>> https://www.newark.com/solid-state/25f40/standard-diode-25a-400v-do-4/dp/07R9506 >>> >>> ** Ah - a stud ( or bolt ) style diode. >>> It will need a fair size heatsink, threaded at 10-32 UNF. >>> BTW the heatsink will be live and dangerous. >>> >>> OTOH, a 25A, 600V metal base bridge rectifier is isolated from the AC power and can be attached to an earthed box or heatsink with any suitable bolt. Just use the + and - terminals. >>> >> >> A good idea, the proper isolation to the heat sink is already present. > > ** Huh?? Wow do you know that ? > >> Or better, for half the voltage drop, so half the dissipation, use (+) and (both of the ~ connected together). > > ** Might stress the reverse voltage handing of the diodes. > >> >> Note that this rectifier method produces a DC component on the mains. >> This may play havoc with transformers and motors on that same mains. > > ** But the OP is not using the mains.Yes, it is a houshold mains application..> > The DC offset effect you allude to is fairly small and rarely a problem. > I have a 1600W hot air gun that uses the same trick to reduce the air temp. > > > > ...... Phil > > > >-- This email has been checked for viruses by Avast antivirus software. www.avast.com
Reply by ●June 30, 20232023-06-30
On 30/06/2023 00:04, John Larkin wrote:> On Thu, 29 Jun 2023 23:37:22 +0100, TTman <kraken.sankey@gmail.com> > wrote: > >> As part of an experiment with solar, I want to drive my 220V 3kW >> immersion heater with a suitable diode so that the effective power is >> ~1.5kW and can be driven by a smart switch so that it doesn't suck too >> much out of the 9.5kWh battery or solar panels.. What diode? This is UK >> spec. > > Is the source the AC line, what you folks call "mains" ? > > If not, the DC component could be a problem. > > I have conjectured that a lot of DC current will slow down an electric > meter, disk or electronic. >Yes, AC line, 220/250V 50Hz.Mains :) -- This email has been checked for viruses by Avast antivirus software. www.avast.com
Reply by ●June 30, 20232023-06-30
TTman wrotr: ------------------- >>> >> Note that this rectifier method produces a DC component on the mains. > >> This may play havoc with transformers and motors on that same mains. > > > > ** But the OP is not using the mains. > > Yes, it is a houshold mains application.. >** Remember posting this? " As part of an experiment with solar, I want to drive my 220V 3kW immersion heater with a suitable diode so that the effective power is ~1.5kW and can be driven by a smart switch so that it doesn't suck too much out of the 9.5kWh battery or solar panels. " I see the words "experiment " , " solar " & "battery" but no sign of the word "mains". ....... Phil
Reply by ●June 30, 20232023-06-30
On a sunny day (Fri, 30 Jun 2023 10:55:12 +0100) it happened TTman <kraken.sankey@gmail.com> wrote in <u7m8q1$2gqfg$4@dont-email.me>:>On 30/06/2023 00:04, John Larkin wrote: >> On Thu, 29 Jun 2023 23:37:22 +0100, TTman <kraken.sankey@gmail.com> >> wrote: >> >>> As part of an experiment with solar, I want to drive my 220V 3kW >>> immersion heater with a suitable diode so that the effective power is >>> ~1.5kW and can be driven by a smart switch so that it doesn't suck too >>> much out of the 9.5kWh battery or solar panels.. What diode? This is UK >>> spec. >> >> Is the source the AC line, what you folks call "mains" ? >> >> If not, the DC component could be a problem. >> >> I have conjectured that a lot of DC current will slow down an electric >> meter, disk or electronic. >> >Yes, AC line, 220/250V 50Hz.Mains :)I'd prefer a triac over a diode to limit any DC (saturation inductors etc) Google has many examples, here is one: https://www.homemade-circuits.com/how-to-make-25-amp-1500-watts-heater/
Reply by ●June 30, 20232023-06-30
TTman wrote: -------------------------> >> As part of an experiment with solar, I want to drive my 220V 3kW > >> immersion heater with a suitable diode so that the effective power is > >> ~1.5kW and can be driven by a smart switch so that it doesn't suck too > >> much out of the 9.5kWh battery or solar panels.. What diode? This is UK > >> spec. > > > > Is the source the AC line, what you folks call "mains" ? > > > > If not, the DC component could be a problem. > > > > I have conjectured that a lot of DC current will slow down an electric > > meter, disk or electronic. > > > Yes, AC line, 220/250V 50Hz.Mains :) >** Think the idea creates an illegal mains installation. The DC component and harmonic currents are both way too large too comply with UK regulations. Also , you may cook your grid tie inverter. ....... Phil
Reply by ●June 30, 20232023-06-30
On 30/06/2023 11:15, Phil Allison wrote:> TTman wrotr: > ------------------- > >> >>>> Note that this rectifier method produces a DC component on the mains. >>>> This may play havoc with transformers and motors on that same mains. >>> >>> ** But the OP is not using the mains. >> >> Yes, it is a houshold mains application.. >> > > ** Remember posting this? > > " As part of an experiment with solar, I want to drive my 220V 3kW > immersion heater with a suitable diode so that the effective power is > ~1.5kW and can be driven by a smart switch so that it doesn't suck too > much out of the 9.5kWh battery or solar panels. " > > I see the words "experiment " , " solar " & "battery" but no sign of the word "mains". > > > > ....... PhilSorry, my big mistake :) -- This email has been checked for viruses by Avast antivirus software. www.avast.com
Reply by ●June 30, 20232023-06-30
>>> P = E^2 / R >>> >>> If you string two heaters in series, you have the same voltage, but twice the resistance, so half the power. >>> >> No, you don't understand this english stuff. Twin heaters are rare in the UK > > Not sure what you are talking about. You want to rig a diode to create half wave AC to drive a heater. That's not exactly "standard" practice anywhere.Correct. Not standard. Read my original post that explains why.> > If you have mechanical limitations, that's what you have. Electrically, this makes sense.No mechanical limitations.> > You could add a resistance in series. It would need to be about 30% of the resistance of the heater. The main element would dissipate half of the original heat. The heat in this added resistance would be about 22% of the heat dissipated in the original heating element. One nice thing about this is that you can tailor the heat in the main element to other than half the original heat level. >No chance. 3kW = ~18 Ohms. Where do I get 18 Ohms 1.5kW rating? -- This email has been checked for viruses by Avast antivirus software. www.avast.com
Reply by ●June 30, 20232023-06-30
On 29/06/2023 23:37, TTman wrote:> As part of an experiment with solar, I want to drive my 220V 3kW > immersion heater with a suitable diode so that the effective power is > ~1.5kW and can be driven by a smart switch so that it doesn't suck too > much out of the 9.5kWh battery or solar panels.. What diode? This is UK > spec. >A big fuck-off Variac is what you need, if you can find/borrow one. [I did use a diode in a very similar though much lower power application. From a magazine idea in the dark ages, I put a diode across the contacts in a mains 'torpedo' switch supplying my uncontrolled soldering iron. Switch on for full power, off for standby.] -- Cheers Clive
Reply by ●June 30, 20232023-06-30
On 30/06/2023 11:17, Jan Panteltje wrote:> On a sunny day (Fri, 30 Jun 2023 10:55:12 +0100) it happened TTman > <kraken.sankey@gmail.com> wrote in <u7m8q1$2gqfg$4@dont-email.me>: > >> On 30/06/2023 00:04, John Larkin wrote: >>> On Thu, 29 Jun 2023 23:37:22 +0100, TTman <kraken.sankey@gmail.com> >>> wrote: >>> >>>> As part of an experiment with solar, I want to drive my 220V 3kW >>>> immersion heater with a suitable diode so that the effective power is >>>> ~1.5kW and can be driven by a smart switch so that it doesn't suck too >>>> much out of the 9.5kWh battery or solar panels.. What diode? This is UK >>>> spec. >>> >>> Is the source the AC line, what you folks call "mains" ? >>> >>> If not, the DC component could be a problem. >>> >>> I have conjectured that a lot of DC current will slow down an electric >>> meter, disk or electronic. >>> >> Yes, AC line, 220/250V 50Hz.Mains :) > > I'd prefer a triac over a diode to limit any DC (saturation inductors etc) > Google has many examples, here is one: > https://www.homemade-circuits.com/how-to-make-25-amp-1500-watts-heater/ >I bought this... It works, but I thought a diode would be a simpler solution... https://tinyurl.com/4ndkfddw AC 220V 4000W SCR Thyristor Digital Control Electronic Voltage Regulator -- This email has been checked for viruses by Avast antivirus software. www.avast.com
