Difference between LV dimmer for incandescent and regular

[danickstr]

i know that the regular dimmer can be used with transformer and incandescents, or at least it used to be fine in the olde dayes, but now they sell a dimmer for use with transformed filament bulbs. is it worth the extra 15 bucks?

 

[al hildenbrand]

To my knowledge, most simple incandescent solid state dimmers have not worked well with magnetic transformers, ever.

Electronic transformers require a different type of dimmer than either the magnetic or incandescent.

So, three different types are made, for good technical reasons.

Now, the electronic transformer may be constructed to work with a simpler dimmer than the electronic low voltage dimmer, but the manufacturer of the transformer has to clearly state so in their product literature.

A good overview is available in this short two page paper from Lutron.

 

[brantmacga]

most ELV transformers (inverters) use reverse phase control (they remove the power from the trailing edge of the sine wave. Not every ELV transformer uses reverse phase control, so check the specs! MLV's use forward phase control (just the opposite of ELV). Most (I only say most because I don't know that 100% of dimmers on the market are constructed this way) standard incandescent dimmer's use forward phase control, and are therefore compatible with MLV's.

 

[al hildenbrand]

standard incandescent dimmer's use forward phase control, and are therefore compatible with MLV's.

I note that the Lutron PDF that I link to above claims that standard incandescent dimmers are not listed to have to have symmetrical forward phase-control waveforms.

 

[brantmacga]

sorry i didn't read that before. that may be something specific to lutron (lemme guess, the "MLV dimmers" probably cost a lot more?? ). I use mostly leviton and ALL of their dimmers are rated for forward phase control MLV dimming. The lutron guide says "positive and negative periods may not be equal, . . .) I'm going to go out on a limb here and say those dimmers are probably 99% equal in components.

 

[al hildenbrand]

Leviton makes nice dimmers, no doubt.

In the world of standard solid state incandescent dimmers, there are a lot of lesser quality than Leviton or Lutron and more limited electronics.

If a standard solid state incandescent dimmer has equal positive and negative forward phase-control waveforms, and the product literature attests to it, then it will probably also be listed for use with a magnetic low voltage transformer.

The cheap incandescent dimmer won't have equal + & - waveforms, and one runs afoul of 110.3(B).

 

[brantmacga]

Leviton makes nice dimmers, no doubt.

In the world of standard solid state incandescent dimmers, there are a lot of lesser quality than Leviton or Lutron and more limited electronics.

absolutely

If a standard solid state incandescent dimmer has equal positive and negative forward phase-control waveforms, and the product literature attests to it, then it will probably also be listed for use with a magnetic low voltage transformer.

The cheap incandescent dimmer won't have equal + & - waveforms, and one runs afoul of 110.3(B).

I think we've just found an instance where that code can be abused by a manufacturer. If leviton can list their dimmer for both, why can't lutron? do you think their 'incandescent' dimmer is of that much lesser quality than their 'MLV' dimmer? I only ask out of curiosity of another electricians opinion.

 

[al hildenbrand]

I think we've just found an instance where that code can be abused by a manufacturer.

I think a chunk of Lutron's quality $$ premium goes into plates & colors & designer features, as much, if not more than the electronics. But I'm probably not a fair judge as my exposure to Leviton's line is less than my exposure to Lutron.

I do believe that Lutron's standard incandescent dimmers are of excellent quality and that the + & - waveforms are not symmetrical.

 

[e57]

Used to get a lot more Lightoilier dimmers - but all the supply houses stopped carrying them due to non-competion clauses in Lutron contracts. Now only the Lighting houses carry them... Rare for me to see a Leviton dimmer, although I see only every other device they make - except dimmers - Lutron again..... And like most all manufactures of certain things - Lightoiler, and Lutron have a high-end, and a low ball... Lots of styles and colors.... Not sure where Leviton goes with this?????

Anyway since it was brought up....
http://www.lutron.com/technical_info/pdf/LutronDimmingBasics.pdf

 

[danickstr]

thanks for replies, I am a bit confused, but will read the white sheets.