[Eeyore]

"Bob H." wrote:

The fridge and the audio system share the same 16A spur. There is
nothing else powered from this branch. The amp has a 2A fuse. What
kind of power does a fridge consume. Not much, I guess.

The problem is not total current, but a very large spike or spikes
caused when a motor turns on, either from the start cap, or arcing in
contacts. The spike is very large (sometimes thousands of volts), and
has a very short time duration, resulting in a very small average
current, but able to make it's way through most filter networks.

You mean when the motor turns off actually.

Graham

[Bob H.]

You mean when the motor turns off actually.

Graham

I don't know what would be causing the pop. It could be a byproduct of
current inrush as the motor starts to turn in concert with the start
cap discharging, it could be contact arcing, aggrevated by the current
inrush as the motor starts to turn.

The post said the pop was when the fridge cut on.

I do know that AC lines are great carriers of these things, and that
most conditioners don't do squat for these types of spikes. Also, many
other factors can create an environement which aid the developement of
spikes. Things like poor on non-existant grounding, dirty contacts,
etc.

In my house, the fridge and microwave have their own breaker. And
sometimes when the fridge and microwave cut on at the same time, they
will throw the breaker, though both devices are rated well below the 15
amp breaker. This only happens when the two cut on at the exactly the
same time, and so it's a very rare occurance, like once a year or so.

bob h.
..

[Eeyore]

"Bob H." wrote:

You mean when the motor turns off actually.

Graham

I don't know what would be causing the pop. It could be a byproduct of
current inrush as the motor starts to turn in concert with the start
cap discharging, it could be contact arcing, aggrevated by the current
inrush as the motor starts to turn.

Contacts don't arc on switch on. They do arc when switching off.


The post said the pop was when the fridge cut on.

No.

" it was plagued by loud mains-borne clicks, which came from the fridge
everytime the compressor stopped. "

This is a classic example of turning off an inductive load using an
old-fashioned mechanical contact system.

Graham

[Bob H.]

No.

" it was plagued by loud mains-borne clicks, which came from the fridge
everytime the compressor stopped. "

This is a classic example of turning off an inductive load using an
old-fashioned mechanical contact system.

Graham

My mistake. Same spike, different event.