ECN Forum Forums General Topics of the Trade General Discussion Area Why are there magnetic dimmers?

Recently I purchased some Lutron Maestro dimmers. When I went back to get more I mentioned to the sales person I was putting in Halo low voltage recessed cans. When she heard that, she told me I needed to purchase the Maestro dimmer not for incandescent but for magnetic transformers. She informed me if I did not the transformer would eventually burn out.

My question is to find out if she is right about this and also learn more about the technicals of why a different kind of dimmer is required for low voltage lighting.

Many thanks in advance,
Byron

I am not an engineer so I can't tell you why, but Low voltage needs a lo-vo dimmer.
Magnetic transformer needs a magnetic dimmer.
Electronic needs an electronic dimmer.

There are exceptions though. Some lo-vo lights require a standard dimmer. The instructions will tell you what is required, no way I'd rely on a sales person.

... From what I understand,fixtures that require electronic x-formers are those where size is an issue..You can get an electronic ballast to fit in smaller places,although the load/watts are generally alot less than it's cousin,the big,ol' clunky magnetic ballast/transformer which is not much more than an iron core with copper windings and a capacitor or two.. Being electronic,utilizes choke coils,and other small semi-conductor parts,thusly requiring the use of an electronic type dimmer control.Failure to do so can result in either x-former failure,or pre-mature dimmer burn-out.I believe hertz(frequency) has something to do with that here..I usually check with the manufacturer,or my rep at the lighting supply house I go to.. Good Luck!!
Russ

[This message has been edited by Attic Rat (edited 01-28-2005).]

This might help: http://www.lutron.com/applicationnotes/362219b.pdf

... Thanx e57,... extremely useful stuff there!! I be printing it tonite!!
Russ

Here have some more!

I give these (and other interesting things)out during the rare dull moments on site, to those interested.
http://www.lutron.com/applicationnotes/

There are a number of approaches to dimming a light bulb.
Simply reducing the voltage works well if you're talking about a standard light bulb.
For motors, the speed is sometimes adjusted by electronically blocking part of the 'pulse' from the AC supply.
For fluorescent lights, dimming is accomplished (in part) by changing the frequency of the AC to the bulbs.

In other words, how you "dim" something depends very much on just what that "something" is. That is why it is essential to match dimmers with the appliances.