Dimmer won't work when connected to power inverter

[Chuck]

Why won't a standard dimmer work when connected to 12VDC to 110VAC power inverter???

I successfully tested an 18ft long section of rope lights (Hunter brand) and a 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?

Why does it work properly on 110V 60Hz household current but not with the power inverter? Thanks.

 

[hr(bob) [email protected]]

Why won't a standard dimmer work when connected to 12VDC to 110VAC power inverter???

I successfully tested an 18ft long section of rope lights (Hunter brand) and a 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?

Why does it work properly on 110V 60Hz household current but not with the 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

 

[David]

message

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

 

[[email protected]]

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

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

 

[Chuck]

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.

 

[hr(bob) [email protected]]

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

 

[Chuck]

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.

 

[Chuck]

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.

 

[Chuck]

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

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