Dimmer won't work when connected to power inverter

inverter???

3-stage touch dimmer in my house before taking out to install it in my RV. After plugging it into my 12VDC to 110VAC power inverter it just has one brightness level which is maximum brightness. Once its on, I can't turn it off again without unplugging it. I tried using a standard incandescent rotary dimmer with the exact same results. Why is this happening?

power inverter? Thanks.

My guess is that if you looked at the output of the inverter it is full of high-frequency noise spikes that trigger the scr on irrespective of where the threshold is set for diming for normal relatively noise-free 60 HZ from the good -old power company. If you listen to a portable AM radio anywhere in the RV, I bet it is almost impossible to hear if the RV is running off the inverter. A large capacitor acroos the line feed ing the dimmer, along with ferrite beads on the input lines might make a low-pass filter that would be effective enough to solve the problem, but I would n't give you more than 50-50 odds. You really need an oscilloscope to look at the inverter output.

H. R.(Bob) Hofmann

More than likely, the inverter puts out square wave and the normal triggering mechanism for these dimmers assumes a sine wave.

David

The high frequency components of the square wave are creating the problem.

Thanks to all for the explanations. Non-pure sinusoidal (square wave) explanation must be it. I will just use the bright output level and an on/off switch and be happy with that.

I'm still curious if you can use an AM radio in the RV when it is running on the inverter?

H. R.(Bob) Hofmann

I will check the am radio reception and get back to you tomorrow.

I broke my rear window top hinge (backed into carport with window open) and so can't get into the back until friday. I will check am radio reception then.

OK. As suspected, the power inverter creates "noise" which of course affects the AM radio signal reception.