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[aprssig] Shack backup power

Steve Noskowicz noskosteve at yahoo.com
Mon Sep 12 00:26:28 UTC 2011


While waiting for the OT police to show up, Steve, K9DCI comments first:

Glad to learn about grid-tie as well.


Then moves on to Bob's remark below as follows.

RE: Bob's two comments:

>  ...to keep the refrigerators and freezers going ...
> A 1 kw generator and a can of gas is hard to beat for economy. 

AND :

> A typical refrigerator is rated at 400 to 900 watts 
> (when running (and defrosting... 


I say OOPS!
What about start-up (locked-rotor).  Having had experience designing (350 W DC Brushless and higher variable speed A/C motor drives) I'm very aware of locked rotor.  I have been using 5-8 times run current to get an idea of locked rotor.  I recently learned that there is a letter on motors with the locked rotor current factor, but don't have a conversion chart.   

What are typical fridge locked rotor values/fctors?

I've only got 1 fridg...
Wagging 800 watt, 6.7A run (no defrost and I'm too lazy to push it out) and 5-8x start, this amounts to 4000 - 6400 surge.  Not a triffle.  I'm pretty sure typical 1kW gensets won't hack this.

For a completely irrelevant example...One of my 400W 800W/surge Coleman inverters has to be switched on before my boat-anchor HP (141T type) spec analyzer that draws (I just measured it - Current clamp) 1.13A or it faults out.

Steve, K9DCI



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