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kenny_10
6th Jul 2018, 10:57 PM
I have several 415V 3 phase electric motors that I want to sell.. but It would be nice to see if they actually work first !..apart from plugging them in to someones factory, is there any other way to see if they are working ?
Ken

BaronJ
7th Jul 2018, 04:02 AM
Hi Ken,

As a first step, you will need a megger, is to check for any winding insulation breakdown to the case ! If they have an earth connection, check continuity to the metal frame. After checking that, then applying a three phase source to see if they run quietly without bearing rumbles. The three phase source could come from an inverter, single phase in, three phase out.

BobL
7th Jul 2018, 08:00 AM
As well as BJs recommendations the winding resistances should all be identical.

Even though they are 3P 415V they will still run on a 3P 240V VFD - they just won't develop full power.

BaronJ
7th Jul 2018, 05:36 PM
Thank you Bob, Yes I completely forgot to mention that. Sorry.
The only thing I would add is take extra care when measuring multi speed motors ! It is easy to make an error comparing multiple windings.