[Elecraft] FW: Lutron dimmers

[Jerry]

GA Jim,

I am in search of replacing over 100 dimmers in our house due to an excavating incident where the neutral was pulled out. I have had direct contact with Lutron's tech service where I expressed my concern for both rfi caused by the dimmers and interference to the dimmers caused by my station.

Fwiw here is the reply (the images didn't copy but were just sine wave representations of operation)  - I went with one of their recommendations

73

Jerry, k1tgx

Good afternoon Jerry,

When dimming you can experience interference with sensitive audio equipment depending upon the type of dimmer and type of bulb you are controlling. The way a dimmer dims is by turning the lights on and off 120 times a second. Based upon the on time of the signal you will either get brighter or dimmer light. Less on time = dimmer light because the lights are not running as long each cycle.

Any forward phase dimming control, could result in a feedback into audio equipment due to the way that dimming signal works. The way a dimmer dims is by turning the lights on and off 120 times a second. Based upon the on time of the signal you will either get brighter or dimmer light. Less on time = dimmer light because the lights are not running as long each cycle.

During this rapid cycling with a forward phase control, there is a spike present before the dimmer turns on each time; we call this repetitive peak (see illustration #1). When controlling incandescent or halogen bulbs you normally will never experience misbehaviors because these bulbs are resistive in nature and act like a filter for the line, suppressing the repetitive peak. On the other hand, LEDs are capacitive and can greatly increase this repetitive peak, resulting in misbehaviors, buzzing or interference. However, since reverse phase or ELV controls dimming signals are completely opposite than forward phase signals the buzzing is greatly reduced if not completely eliminated (see illustration #2). There are two things to be aware of with ELV controls, 1) these types of controls require a neutral connection to be present at the location of installation (bundle of white wires connected together). 2) These controls are normally 2 to 3 times to cost of standard incandescent or LED dimmers.

Illustration #1



Illustration #2


You can view our LED selection tool at www.lutron.com/ledtool<http://www.lutron.com/ledtool>. This LED selection tool will allow you to generate a list of compatible LED products for all of our LED rated dimming controls. You will all be able to access a testing report for each of the LEDs listed here. The report will provide you with a list of all the dimmers we can recommend for that LED, the amount of LEDs each dimmer can control and the dimming range you will experience.

If looking for ELV solutions on our LED selection tool, select "reverse phase" from the control technology menu. Also, here is a list of ELV controls that we can recommend for use with LED products.

*             MRF2-6ELV-120
*             RRD-6NA
*             HQRD-6NA
*             PHPM-WBX-DV-WH
*             PHPM-PA-DV-WH
*             LP-RPM-4A-120
*             HW-RPM-4A-120

Please let me know if you have any questions

Sincerely,
Matt Rehrig
Lutron Support
Lutron Electronics, Inc.
www.lutron.com<http://www.lutron.com>
MR