hum when two devices plugged in

Gentlemen, no matter how far away they are in the house from each
other, when I plug in

*Electric blanket (with sine wave chopping current limiter) +
uninterruptible power supply, (attempt to keep warm and use a
computer at the same time) or

*Electric frying pan (with sine wave chopping low power setting) + 12 V
amateur radio power supply (attempt to cook something and not have to
turn off a ham radio)

I get this terrible hum out of the latter of each, due to some kind of
electrical resonance. Is there some kind of electronic filter one can
use?

Each sine wave chopping device is just a LOW-MED-HIGH switch that does
something funny to the AC wave form as a simple way of cutting down
from full power.

[Also posted on http://en.wikipedia.org/wiki/Talk:Electrical_resonance ]

 

[Jamie]

jidanni@jidanni.org wrote:

Gentlemen, no matter how far away they are in the house from each
other, when I plug in

*Electric blanket (with sine wave chopping current limiter) +
uninterruptible power supply, (attempt to keep warm and use a
computer at the same time) or

*Electric frying pan (with sine wave chopping low power setting) + 12 V
amateur radio power supply (attempt to cook something and not have to
turn off a ham radio)

I get this terrible hum out of the latter of each, due to some kind of
electrical resonance. Is there some kind of electronic filter one can
use?

Each sine wave chopping device is just a LOW-MED-HIGH switch that does
something funny to the AC wave form as a simple way of cutting down
from full power.

[Also posted on http://en.wikipedia.org/wiki/Talk:Electrical_resonance ]
You need an isolated Xformer, large common mode choke or reactor on one

of the devices.
or, use a different outlet that is off the other side of the tap of
the pole pig.


http://webpages.charter.net/jamie_5"

 

[Rose]

On Dec 3, 2:20 pm, jida...@jidanni.org wrote:

Gentlemen, no matter how far away they are in the house from each
other, when I plug in

*Electric blanket (with sine wave chopping current limiter) +
 uninterruptible power supply, (attempt to keep warm and use a
 computer at the same time) or

*Electric frying pan (with sine wave chopping low power setting) + 12 V
 amateur radio power supply (attempt to cook something and not have to
 turn off a ham radio)

I get this terrible hum out of the latter of each, due to some kind of
electrical resonance. Is there some kind of electronic filter one can
use?

Each sine wave chopping device is just a LOW-MED-HIGH switch that does
something funny to the AC wave form as a simple way of cutting down
from full power.

[Also posted onhttp://en.wikipedia.org/wiki/Talk:Electrical_resonance]

Is it your electric frying pan that hums?