# Runnig a 3ph motor on 220 1ph?



## calstar (Mar 8, 2014)

I looked at a 1965(?) Index 645 yesterday, the owner was running it off of a dedicated 220 circuit, followed line back to the panel,  no phase converter in sight, he did not know what one was. How is this possible? 

the motor




BTW its for sale(not by me and don't know the owner), he got it a year ago and never used it. Has a lot of wear, definitely  a "project"(too much for me). He's asking 2000 but said he's open to offers, he wants it gone. Here's a link:

http://santabarbara.craigslist.org/tls/4353180838.html

PM if interested, maybe I can help facilitate the sale


Thanks, Brian


----------



## John Hasler (Mar 8, 2014)

calstar said:


> I looked at a 1965(?) Index 645 yesterday, the owner was running it off of a dedicated 220 circuit, followed line back to the panel,  no phase converter in sight, he did not know what one was. How is this possible?
> 
> Thanks, Brian



Static converter circuitry squirreled away inside?  Just takes a relay and a couple of capacitors.


----------



## vapremac (Mar 8, 2014)

Yep ,it can be done ,actually its done a lot. 220 will get the motor spinning with no trouble,
but without the third leg connected you lose 1/2 of the rated horsepower. Its not "healthy"
for the inner components as the voltage is not balanced across the three legs.
 Basically ,those small static phase converters available commercially are just a way of
balancing out the voltage and the specs on them tell you that you will lose roughly half
of the motors rated HP.
 I have actually seen the same machine wired to a static phase and rotary phase and the
dramatic difference in the surface finish on the work piece due to the constant voltage
spikes from a static phase.

William


----------



## Ulma Doctor (Mar 8, 2014)

a static converter can be made with 1 capacitor ,1 relay, a momentary stop and a momentary start wired together correctly

I made and posted the plans for a simple unbalanced RPC for anyone interested.
Click the link below:

http://www.hobby-machinist.com/showthread.php?t=12712


----------

