David Farber wrote:
Phil Allison wrote:



** That is normal.

The rotor is a magnet, deliberately used in an asymmetric
arrangement with the stator.

When I powered it up on the
bench, the motor shakes quite a bit.

** But does it turn ?

I found a rubber band stuck inside one that stopped it turning under
its on power. You need to take a look.


The motor does turn but it vibrates above and beyond any motor I've ever
encountered. (It would be great if you installed in one of those chairs that
give you a back massage.)


** That is normal - for the reason I just gave you.


The explanation in this video,
https://www.youtube.com/watch?v=M0W9pzBZ-DI says the motor should have a DC
input resistance of 200 ohms.


** The video id from the UK where the AC power is 240V.


Though I can understand there will be
variances between every motor, this motor measures 20 ohms between the input
terminals.


** That is also normal.

The line draw as registered by my Sencore PR57 is just under 100
watts at 120VAC. The sticker on the motor says 40W.


** Your Sencore does not measure true watts as it does not take account of power factor which could easily be 0.5

All the numbers you quote are OK.



..... Phil