SCR dimmer control for portable electric heater??
in [Repair]
|
Prev: Wanted VCR schematic Magnavox CMWV405
Next: solutions manual to Fundamentals of Logic Design, 5th Ed., by Charles Roth
From: isw on 20 Mar 2010 23:17 In article <ho40m3$t33$1(a)news.eternal-september.org>, "William Sommerwerck" <grizzledgeezer(a)comcast.net> wrote: > >> Does anyone know of an SCR control hefty enough > >> to handle this kind of resistive heating load?? > > > Or (maybe) better yet, how about some kind of PWM > > control? > > SCR dimmers use PWM. > > I rather like the idea of wiring two heaters in series. This will reduce the > total output to half of what it was, but it will be better spread around the > room, which might be a net improvement. It will reduce the current to (approximately) half, which will reduce the heat output (power) to one-quarter that of a single unit. Power is I^2*R. Isaac
From: Phil Allison on 21 Mar 2010 01:17 "isw" > "William Sommerwerck" > >> I rather like the idea of wiring two heaters in series. This will reduce >> the >> total output to half of what it was, but it will be better spread around >> the >> room, which might be a net improvement. > > It will reduce the current to (approximately) half, which will reduce > the heat output (power) to one-quarter that of a single unit. Power is > I^2*R. > ** But there are now two heaters in series, R is doubled so the power is half. ..... Phil
From: William Sommerwerck on 21 Mar 2010 06:42 >> I rather like the idea of wiring two heaters in series. This will >> reduce the total output to half of what it was, but it will be >> better spread around the room, which might be a net improvement. > It will reduce the current to (approximately) half, which will reduce > the heat output (power) to one-quarter that of a single unit. Power > is I^2*R. But there are two heaters. Two times 1/4 = 1/2.
From: petrus bitbyter on 21 Mar 2010 09:45 <me(a)privacy.net> schreef in bericht news:bqoaq5908icln7fg4b3bghljmc13cu801h(a)4ax.com... >I have one of those 1500 watt radiator style portable > electric heaters. Love it > > However, rather than the built in thermostat turning > the unit OFF?ON every 15 min's or so, I was thinking > it would be more efficient to use an SCR dimmer control > to vary the amt or power it gets? > > Does anyone know of an SCR control hefty enough to > handle this kind of resistive heating load?? Ever build a thing like that as I could not find it on the market at the time. Used a 555, a dual pot and an SSR that could handle over 250Vac/20A. The SSR had a build in zero cross detector so I could switch on between 1 and 100 halfcycles within a 50 cycles period. Worked as advertised though it was not very cheap mainly caused by the price of the SSR. petrus bitbyter
From: [SMF] on 21 Mar 2010 11:58
On 3/20/2010 8:01 PM, me(a)privacy.net wrote: > David Nebenzahl<nobody(a)but.us.chickens> wrote: > >> Or (maybe) better yet, how about some kind of PWM control? Wouldn't that >> be even more efficient (the control device is either on or off, so >> little thermal losses)? Just an idea ... > > Yeah that would work also.... > > Thing is I was hoping it possible to find such a > control for maybe $30 or so.....as the dang heater only > cost $40. lol > > Anyway...... just thought controlling heat output that > way (vary power) better than on/off thermostat. The on/off cycling of the device is not only for ambient temperature, but is also for device safety. The unit will cycle on and off until the thermostat temperature set point is reached. |