Sam Goldwasser wrote in message ...
"Rheilly Phoull" writes:

"Thurston Phoremost" wrote in message
om...
I have a cyclic defrost fridge in near-new condition which was given
to me, the only problem was the defrost element open circuit.

Well, that fridge has been sitting there for a year, and now that I
decide to fix it, I find the compressor won't start. She hums, likea
the buzzy bee, then the overtemp protector clicks out.

Question - I know that the fridge mechs have a device that they
connect up to send a bit of a boost thru the compressor to unstick it,
but I'm a bit tight, and if I can rig up a relay and/or a capacitor
and/or a triac and/or an instantaneous switch or whatever to do it
myself, I will.

What's the general principle of it? Am I correct in assuming that the
idea is to connect a capacitor across the inductance of the start
winding to make a LC circuit whose resonant freq is close to mains
freq, so that you can get a lot of current flowing for a small
fraction of a second?

So... how do I make one of these gizmos? Can't be too hard, surely?

And if you do it incorrectly, you've fried the compressor motor and turned
your fridge into a plant stand.

Yup. That's why I'm asking here, to get enough info so as I don't do
it incorrectly. I won't do anything till I have as much info as I can
get.


You really don't even know if the
motor is stuck. Maybe the starting relay is stuck. Have a professional
look at it. Really!

The relay looks like it can't be taken apart. I'd be interested to
know if anyone has ever tried to test these things with a dummy load,
for instance in the same way that you can use light bulbs as a dummy
load to test a SMPS?

Does an easily audible hum from the compressor
generally/probably/usually indicate that the start winding is getting
current? IOW, if only the run winding is getting power, would I still
get an easily audible hum?

If only the run winding in a stuck compressor was drawing current,
would this current generally/probably/usually be sufficient to trip
the safety switch, or is it only the start winding that has
sufficiently low impedance to cause it to trip?

This is the sort of info that I am after. TIA.


T