Dimming Tech Lighting

[Mike The Mute]

I've never been a fan of Tech Lighting. It's like painting a turd gold, all you end up with is a gold colored turd. Anyway, my latest problem has been that my customer wants to use Lutron Maestro series dimmers. I installed an Electronic Low Voltage dimmer at the switched side of the 3way (as per directions to tie the swith leg neutral to the dimmer), but it hums so loud I can almost tell what it's saying (at the transformer). It was a 1000w dimmer.
The manufacturer was useless. Typical. Today it seems like all technical questions are answered from a computer prompting them as to what to say. Whatever happened to trained technical advice? Guess we have Mike Holt to thank for there still being somewhere to turn.
I'm not one for trial and error. Especially when it may burn up an overpriced, lead-laced, "made in china" gold turd of a transformer. Anyone out there know what may be the best solution?
Thank you all, Mike
P.S. During the install there was a series of issues of shorting out the coax style wiring that feeds/supports the 5 pendants coming from the transformer. Is it possible there is enough of a short to make the dimmed fixture hum, but not enough to cause a noticeable problem without the dimmer?
P.P.S Just an example of what you get for a grand: The 3 metal rods that support the outer glass away from the inner is done in a way that when the rod heats up from the halogens, the rods broke one of the outer glasses. $80 and no admission of guilt from their engineers.

 

[Dennis Alwon]

I would call Lutron. I have experienced a similar problem and the manufacturer told me that a Nova LV dimmer was the only way they would assure no hum. I bought the $80.00 dimmer and it still hummed. I think the bulbs coulb be the problem.

We have changed both transformer and dimmers and nothing seems to work. Lutron says that they did not have this manufacturers as one of their safe to buy from group.

I don't think the maestro will help.

 

[Jljohnson]

I have had luck with uing the "de-buzzing" coils that tech lighting will be happy to SELL to you (it should come with every transformer, since they all buzz). Also have had luck experimenting with different manufacturer's of MR16 lamps. GE lamps seem to be the best bet.
Good Luck

 

[gar]

080912-2010 EST

Mike The Mute:

If I understand what you describe it appears you have incandescent lamps, and are using a "phase shift to turn on" type of dimmer. This produces a very rapid rate of rise of voltage. If you phase shift 90 degrees, then the nearly instantasneous rise of voltage is from 0 to about 170 V every half cycle.

It is my guess that if you used a Variac for the dimmer you would be no more noisy than if you eliminated the dimmer. This is not practical both from size and cost but only illustrates that noise free dimming is possible.

A 25 kHz chopper type of dimmer on the output side of the transformer would eliminate the problem, or this type of dimmer at at line voltage at the input of a high frequency transformer. Are any made I do not know? Whether there might be an FCC problemI also do not know.

The load current for 1000 W at a low voltage like 12 V would be about 83 A. Is this what you are dealing with?

For my hall lights I use 120 V small wattage bulbs, and a standard phase shift dimmer. In over 20 years since I installed these fixtures I have never replaced a bulb because these are seldom run at full voltage.

If a location is normally not going to be at full brightness why go to low voltage?

Incandescent lamp life goes up very rapidly with lower voltage relative to the nominal rating, color temperature goes down, and efficiency goes down.

.

 

[SpiderMT]

Lutron Maestro in electronic low voltage is not available in 1000w, it is a 600w dimmer. The magnetic low voltage are available in 600w and 1000w. Maybe you have a magnetic dimmer and electronic transformer? Or more likely you have a magnetic transformer and electronic dimmer. Can you set a remote transformer in attic space or something? If you can move the transformer where you can't hear it then who cares if it buzzes.