Replies

1. 
   OneofmanyBobs | Jan 16, 2005 02:13pm | #1

   Should not be too hard.  Biggest difference is that the speed of a DC motor for the feed can easily be changed.  3-phase won't do that simply.  Needs another way, such as 2-speed motor, variable frequency drive or mechanical system.  So far as interlocks, the 3-phase stuff needs 3-pole switches or relays.  Single-phase or DC needs only one or two poles, depending.  Take pictures of anything electrical and post them.  The schematic for the new machines probably has no similarity to what you have.  People should be able to make some good guesses from the pictures and tell you how to proceed further.  Obviously, unplug everything before poking around inside.

2. 
   WillGeorge | Jan 16, 2005 03:21pm | #2

   but I cannot get all to work together through the safety switches.  ..

   I would start there, the switches... As I have no idea what you have, I will make some assumptions (you know what that means) and be general about machines I have worked on in the past.. Usually safety switches are wired in series to a controlling relay/contactor that turns off/on one or several motors. Sometimes safety switches control different relays or circuits that in turn control others.

   If the motor(s) are 3 HP. they are 220 volts and the power is interrupted on both sides of the line (Is the motor single phase?). I would doubt that the power to the motors go directly through any of the safty switches. There is probably a control relay/contactor operated by a low DC voltage that goes in series threw the switches.

   Get some paper and make a drawing of each safety switch and trace the wires from each side of the switch to it's destination. Do you have a multimeter to measure continuity of the safety circuit? If not you can get a cheap one for a few bucks.

   If you can wire the motors your self you CAN figgure it out! Just making a little drawing while tracing the switch and motor wires (all power removed) should make something click about how they control the motors.

   All it takes is just one broken/loose/pinched wire in a safty circuit to kill the whole thing.  Good luck..  And what was stated about posting some pictures sounds good to me. Lots of smart folks come in here...

3. 
   RickL | Jan 16, 2005 09:08pm | #3

   I do a lot of basic electrical work in our shop but use a qualified electrician for the most part. Best spent money overall in the long range. Make sure the electrician is qualified in motor controls. You might also try calling you local electric motor repair shop to do a house call. Right up their alley.