cupoftea
Advanced Member level 6
Hi,
Obviously the easiest and cheapest way to dim a room-full
of lights (or even an office block full of lights) is to have a phase cut dimmer. you simply phase
cut the mains to the lights. This method needs no extra signal
wires to go to the lights.
Also, purists would criticise the poor power factor of this method.
However, since the phase-cut lamps draw less energy than non-phase-cut
lamps, this is actually a moot point.
If you are drawing less current by way of phase cutting, then the overall current draw
is likely to be less, and thats what power factor laws are mainly about.
So as we know, multi kilowatt mains phase cutting lamp drivers are
allowed by all regulations the world over. The mains harmonics regulations
state that their requirements are not needed for phase cut dimming systems.
So forget EN61000 for your 120A mains phase cut dimmers...its juts not required.
But why do we not see "symmetrical" phase cut dimmers"? (SPCD)
SPPCD's cut the mains half cycle on both trailing and leading edges so that
the power factor is improved.
I realise that the standards don't look at power factor (or mains harmonics) for phase cut dimming systems,
but wouldn't it be a good thing? (SPCD)
Obviously the easiest and cheapest way to dim a room-full
of lights (or even an office block full of lights) is to have a phase cut dimmer. you simply phase
cut the mains to the lights. This method needs no extra signal
wires to go to the lights.
Also, purists would criticise the poor power factor of this method.
However, since the phase-cut lamps draw less energy than non-phase-cut
lamps, this is actually a moot point.
If you are drawing less current by way of phase cutting, then the overall current draw
is likely to be less, and thats what power factor laws are mainly about.
So as we know, multi kilowatt mains phase cutting lamp drivers are
allowed by all regulations the world over. The mains harmonics regulations
state that their requirements are not needed for phase cut dimming systems.
So forget EN61000 for your 120A mains phase cut dimmers...its juts not required.
But why do we not see "symmetrical" phase cut dimmers"? (SPCD)
SPPCD's cut the mains half cycle on both trailing and leading edges so that
the power factor is improved.
I realise that the standards don't look at power factor (or mains harmonics) for phase cut dimming systems,
but wouldn't it be a good thing? (SPCD)