dimmers

[al hildenbrand]

Re: dimmers

Thanks Rattus,

That helps.

Over the years I've had the experience of introducing individuals to how a simple 600VA incandescent only solid state dimmer switches itself on and off. Again and again, the initiate will be expecting the dimmer to be working hardest when the dimmer is dimming the light to the lowest level.

It is my experience that the initiate intuits that the energy not getting to the bulb, has to be "somewhere", so it must be being "wasted" in the dimmer.

The increase of the voltage drop across the dimmer as the dimmer is closer to operating the bulb at maximum brightness, accentuates the counter-intuitive behavior of the dimmer.

That is, the dimmer is hottest when the bulb is the brightest while the triac is still in the circuit (not bypassed by the FULL ON mechanical switch present in most dimmers with mechanical controls).

 

[rattus]

Re: dimmers

Let me modify an earlier statement:

If we chop out a quarter cycle between zero crossing and a negative or positive peak, we have reduced the power to the lamp by 25%--ignoring the loss in the dimmer. If we chop out two quarter cycles, we reduce the power to the lamp by 50%, etc. However, any other reduction in duty cycle requires calculus to calculate the net power.

[ January 22, 2006, 11:26 PM: Message edited by: rattus ]

 

[kalanjeya]

Re: dimmers

al hildenbrand , I am here to aside you, but i am saluting rattus for his patience.

 

[al hildenbrand]

Re: dimmers

&#191aside?

 

[mario]

Re: dimmers

yo guys ... I finally got my tools out and checked the amp draw on the lights ... 5 90 watt floods at full "On" 4.5 amps ... at "max dim" 1.5 amps ... must be I'm saving "money" when they're dimmed ... I checked this at the dimmer around the "Hot" into the switch ...
anything else ... M

 

[kalanjeya]

Re: dimmers

Originally posted by mario:
yo guys ... I finally got my tools out and checked the amp draw on the lights

Well ! thanks.

But,mario u made mistake here, you should have checked the voltage or current at input of the dimmer not output of the dimmer.you just checked the regulated supply not the power consumed at the circuit. please .... will you do it..

Jeyakumar

 

[rattus]

Re: dimmers

Jeyakumar,

Mario did check the input current which must be the same as the output current since the dimmer is in series with the load.

Now, unless Mario used a true RMS ammeter, his results will not be exact, but they do indicate a reduction in current, Likewise, there will be a reduction in voltage to the load.

No question about it. The power to the load and the power in the dimmer are reduced when the lights are dimmed!

 

[mario]

Re: dimmers

I was using a T-5 at the "Input" ... I wanted to check the voltage drop also to see if it changed but didn't have a second set of hands to stab into the wirenuts ... would that have changed??
is previous post saying I should/would get a different reading if I checked the Neutral wire??
keep it coming if theres more ... M

 

[kalanjeya]

Re: dimmers

Originally posted by rattus:
Jeyakumar,
No question about it. The power to the load and the power in the dimmer are reduced when the lights are dimmed!

O.K,O.k,O.k,O.key ...............rattus.

Jeyakumar