MOV selection and specs (fwd)

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---------- Forwarded message ----------
Date: Fri, 25 May 2007 18:02:53 -0500
From: Andrew Nettles <anettles@xxxxxxxxxxx>
To: tesla@xxxxxxxxxx
Subject: MOV selection and specs

I’m trying to order some MOVs to protect my sync motor and for my 
transformer input.  I’m using a 120v 15/60 NST.

Is DigiKey P7231 the right one?

The spec sheet says the Maximum Allowable Voltage is 150V AC and 200V DC – 
is that 150V RMS?  But I’m also confused about a couple of other specs.

Max Clamp Voltage at Test Current.  That says 395V at 100A (yet the "maximum 
allowable voltage" is 150 and the surge current is 6500A??)

Then there’s Varistor Voltage +/- 10% and that says 240V.

Can someone shed some light on going about selecting the right ones for the 
job?  It seems like I would want to pick something that clamps at about 120 
x 1.414 which is 170V with maybe a little more headroom.

Once I have them, they go between all the pairs of wires on the line filter 
– hot/neutral, hot/gnd, and neutral/gnd – right?

Thanks for all your help!

Andrew in Fort Worth