[rescue] adding power redundancy to single power supply systems ?

Geoffrey S. Mendelson gsm at mendelson.com
Tue Mar 25 01:00:46 CDT 2008

On Mon, Mar 24, 2008 at 10:45:16PM -0400, Patrick Finnegan wrote:
> That's different because it's a generator, where you can actually sync
> it up to the power input.  Trying to do something like that on two
> separate utility lines (or anything that's not designed for it) it a Bad
> Idea.

We have a large refrigerator and clothes dryer on the same circuit. 
(don't ask why).

I had a friend who repairs appliances build a unit with a relay wired 
across the timer on the dryer to cut power to the refigerator while 
the dryer was running.

To prevent problems with the compressor and "hiccups" due to someone
starting the dryer with the door closed, or adding clothes at the
last minute, he installed a time delay unit. 

The unit was cheap (around $20). He bought it at an appliance
parts store. It delays the power coming on for 4 minutes.

If you can get two of them, with different times, you can 
use them to prevent constant switching on and off of the power
lines. You just have to make sure that your UPS can handle the
load for at least the longest delay time.


Geoffrey S. Mendelson, Jerusalem, Israel gsm at mendelson.com  N3OWJ/4X1GM

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