dimmers

[securespark]

Whatever you use, Adam, make sure it is insulated, you don't want a shock disposing of it.

Hmm. Disposing of it.....maybe you could take it back to the CEGB and get a refund, you know - X pence per kW......that is if it hasn't jumped out by the time you get there.

 

[breezer]

Whatever you use, Adam, make sure it is insulated, you don't want a shock disposing of it.

Hmm. Disposing of it.....maybe you could take it back to the CEGB and get a refund, you know - X pence per kW......that is if it hasn't jumped out by the time you get there.

how about using an ELCB

Extra Large Collection Box, shouldn't escape out of that 'cos its extra large

 

[AdamW]

resistive dimmers produce a huge amount of heat and so would be massive

Good point, the old rheostats at school always got quite toasty.

phase cutters use a triac and only turn on the light for part of the cycle theese are small and not hugely expensive but the harmonics they produce can cause a problem either as noise (big stage dimmer packs buzz like hell) or as EMI/RFI

Thinking about it, that would make sense, and would explain why energy saving bulbs flicker when you try to use them with a dimmer intended for incandescent bulbs.

But I had wondered about the harmonics and interference, what I would imagine to be "phase cutting" would produce high-frequency components.

I've learned something today!

 

[ban-all-sheds]

But I had wondered about the harmonics and interference, what I would imagine to be "phase cutting" would produce high-frequency components.

Ever tried putting an AM radio next to a dimmer switch?

Guess what....

 

[kendor]

resistive dimmers produce a huge amount of heat and so would be massive

Good point, the old rheostats at school always got quite toasty.

phase cutters use a triac and only turn on the light for part of the cycle theese are small and not hugely expensive but the harmonics they produce can cause a problem either as noise (big stage dimmer packs buzz like hell) or as EMI/RFI

Thinking about it, that would make sense, and would explain why energy saving bulbs flicker when you try to use them with a dimmer intended for incandescent bulbs.

But I had wondered about the harmonics and interference, what I would imagine to be "phase cutting" would produce high-frequency components.

I've learned something today!

Because they were in series with the load, a Variac is more suitable.

 

[kendor]

A dimmer switch works by chopping bits out of the AC waveform, it expects an un broken wave form to start with,

Isn't a dimmer was just a variable resistor? I.e. it varies the amplitude of the AC waveform rather than "chopping bits out of the waveform".

Is the waveform chopper a special dimmer, for something else?

A phase angle Dimmer does alter the AC waveform by triggering( or gating) the output triac at a certain point in the cycle(which the user has defined by rotating the knob/pot) and it is this voltage that is seen at the output, therefore it is a "chopped" Waveform.