On Mon, 6 Oct 2003 16:59:20 +0100, John Armstrong
wrote:

I don't know much about
pumps, but surely the pump only draws the power needed to keep it running?

No, that is basically the problem.

Look at a workshop compressor. Any modern one will have an "unloader
valve" (You can hear this hiss whenever the compressor motor cuts
out). The function of the unloader is to empty the compressor cylinder
of compressed air, so that next time it starts up it's pumping into a
low pressure, rather than trying to start against an already full
cylinder. As it is, workshop compressors pull a huge current at
startup and running one without an unloader would pop the fuse on a
domestic supply.

Fridges (of any sort) don't have such valves. There's a natural
reluctance to add any such potential leaky valve to a sealed
regrigerant system. So when a fridge compressor starts, it's pumping
into a high load. Such a compressor motor must thus be rated for its
starting power, which is over-rating it for the running power.

The Savaplug reduces motor power electrically, after a small delay
from first starting. It's a good idea, although the original plugs
were far from cheap. It's also an idea that's easy to build inside a
new fridge, and my understanding is that many of them now do so.

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Die Gotterspammerung - Junkmail of the Gods