switching a 440v lathe to 220v

[dannystooblue]

OK, I bought a lathe that was wired 440, after getting prices I decided to change the thing to 220v 3ph and use a phase converter I already have. I got the motor and wired it as required on the motor tag. I then ordered the contactor coil that was 44ov to replace it with 220v. I installed everything and the lathe ran for a few seconds before it stopped. I opened the box where the starter/contactor was to find a smell i really dont like... it smelled like that majic blue smoke like when I killed that poor little servo so long ago, well maybe not that bad. The starter is an AB size 0. was there something else that i should have changed in the starter? or should the entire starter be replaced? it is rated for 3hp motor at 220v, my motor is 3hp and 22ov. Any help would be appreciated.


Danny

[mxtras]

Does the motor starter have "heaters" in it? This alone might be the issue.

What is the rated coil voltage of the contactor and what is the voltage being supplied to that coil?

Scott

[dannystooblue]

I changed out the coil over to 220v. It does have heaters, i am unfamiliar with these, what are their purpose?

Danny

[Al_The_Man]

Check to see if the cause of it stopping is if overload tripped, if so as Scott intimated, it will need higher capacity overloads, if heaters (3) then you need to get the number of the higher current type, is it an Allen Bradley contactor? if so there should be a code # on printed on the outside of the heater.
The motor takes approximately 2x current on 220.
Al.

[dannystooblue]

What exactly is the job of the heater? how does it work? It does have heaters but i have not pulled them out yet to check there size.

Danny

[Al_The_Man]

The overload consists of three heater elements that are in series with each phase, if an overcurrent occurs on a phase, the element heats up an opens a bi-metal trip that has to be manually reset.
The bi_metal opens a normally closed contact that can be used for dropping out the contactor, usually in series with the coil.
If repeated trips occur, the trip occurs more frequently until the element cools down.
They are rated by carrying current and should be marked with a code #.
Al.

[dannystooblue]

Ok, now I have another question, this time about a 2hp 3-phase motor on a knee mill. I got it from a friend that had to move away in a hurry. When he bought it the motor was wired high voltage. The wires were not well marked coming out of the motor and the name plate on the motor is almost unreadable. I need to figure out how to wire this motor to run on low voltage, can you help me identify the wires coming out and how to attach them to make the motor work?

Danny

PS lathe is running now but I don't think my phase converter is large enough, when I try to run at highest speeds the converter starts making noise like its struggling then the heaters kick out on the starter... runs fine at lower speeds.

[mxtras]

Take a peek at this:

http://www.usmotors.com/Service/faq9.htm

Scott