L.V. dimmers

[charty]

How do incanescent dimmers differ from low voltage dimmers in their construction?
Also, I was told today by a coworker that it is ok to use incandescent dimmers on low voltage lighting if the transformer is on each individual light. As opposed to one transformer on multiple lights. I have always used low voltage dimmers for both of those applications. I was always told by factory reps. that tranfomers could be damaged if they are dimmed with an incanescent dimmers. What are your opinions?

 

[d and o]

Re: L.V. dimmers

transformers are hard to hurt

and

power in equals power out

[ December 11, 2003, 08:18 PM: Message edited by: d and o ]

 

[big john]

Re: L.V. dimmers

This is sort of a stab in the dark, but a lot of dimmers are solid-state: Pulse-width modulators or pulse-amplitude modulators. The work by modifying the characteristics of the AC sign-wave going to the load. The output of those dimmers might affect how well a transformer would work, as most power transformers are designed to work nominally on a 60Hz sine-wave.

But, I'd definitely agree with d and o: It takes some pretty significant abuse to fry a big chunk of steel and copper.

-John

 

[charty]

Re: L.V. dimmers

True, but how about electronic transformers. How about when a customer is complaining about the low voltage lights flickering because you have installed an incanescent dimmer on them.Do you think that customer would be confident in your electrical knowledge?

[ December 11, 2003, 08:45 PM: Message edited by: charty ]

 

[electricmanscott]

Re: L.V. dimmers

All the incandescent dimmers I use state that they are for incandescent loads only. Using them otherwise is a violation. I always use the proper dimmer for the application. Low voltage dimmers, both magnetic and especially electronic are much more expensive than standard dimmers. Higher profit margin! I recently had an inspector check the dimmers to make sure they were the right type. First for that one.

 

[mikeames]

Re: L.V. dimmers

If you dim a lv xfmr with a regular dimmer you will severly shorten the life span. In addition to that you will mostlikely hear a buzzing noise and also over load the dimmer. Most incandessent dimmers use a half cycle which will reduce the frquency to 30 hz. This results in a smaller magnetic flux which is in dirrect correlation with the impedance of the coil in the xfmr. Ohms law---Less impedance = more current. Not a good idea for a professional installation.

 

[charty]

Re: L.V. dimmers

i can't believe that there are electricians that would use incandescent dimmers on low voltage lighting.

 

[luke warmwater]

Re: L.V. dimmers

Seagull recommends dimmers to be placed on the line side of the transformer.
If it is a magnetic ballast, they recommend an incandescent dimmer.
If it is an electronic ballast, the recommend a low voltage dimmer.