Unisaw wiring problem

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Old 12-31-08, 11:03 AM
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Unisaw wiring problem

Greetings all! I'm an amateur woodworker and purchased a used Unisaw that dates to around 1970. The saw has a 2hp, single phase, 115v(24a)/230v(12a) Delta(Baldor) motor, an original low voltage controller, and an original magnetic push button switch. I had an electrician configure the motor and lvc for 115v and install a new plug, receptacle, and 30a single pole breaker. Tried it and got absolutely nothing. I asked the electrician about it and he told me that itís probably the motor. Brought the entire saw to motor shop #1(big mistake) and wound up paying $150 for him to take off the motor, take it apart and give it back to me. Told me the motor needed all kinds of work, etc. It looked very good to me so I brought it to the second motor shop and he said it looked fine, put it together, and told me it runs fine. I brought it back home and examined the lvc closely. The wire from the switch to the lvc was bad so I replaced that. All the wiring in the lvc seems be exactly like the schematic and the condition of the unit appears good. I rewired everything as it should be andÖ..nothing. Here is where I have questions. I have a 3 phase service in my building so is this a problem with the single phase motor? From the motor, there is a group of 3 wires and a group of two wires. Iím assuming that the 3 wire group is the hot and the two wire group is the neutral. Iím at a loss and would like to restore the machine with original components. I can take pictures as well. Thanks in advance!!
 
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Old 12-31-08, 11:19 AM
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I would ask the second motor shop how they hooked it up. Did they hook it to 120V, or 240. Did they leave the connections as they are, and plug the cord in to a receptacle?

Is there a wiring diagram inside the connection cover. Every dual voltage motor I've seen has a diagram that shows how to connect the motor leads depending on the supplied voltage. Usually for 120V it would show which leads are connected together and it would also show how to connect to L (hot or "line") and N (neutral).

What kind of plug and receptacle did the electrician provide? 20A? 30A? What is the configuation?

Shouldn't matter if you have 3-phase power when hooking it up for 120V. 120 is 120 whether from a single or three phase system. You may have a problem trying to hook it up 230V, because your system outputs 208V. If the motor is not rated for 208, you would have to install a buck/boost transformer to boiost the 208 to 230. If you tried to run it on 208, it would run at a higher current which could damage the motor windings.
 
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Old 12-31-08, 12:44 PM
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Pictures

Here are the pictures:

dgr68 - Photobucket - Video and Image Hosting
 
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Old 12-31-08, 12:50 PM
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Motor Shop

Second motor shop tested it at 120v I believe because they told me it was wired that way. The wiring from the motor is correct based on the diagram. As I didn't take it apart, I'm not sure if the set of three wires connects to the black wire from the controller or the white wire. It's not clear in the diagram.
 
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Old 12-31-08, 01:21 PM
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If you have a low voltage controller you have to have a low voltage transformer. Are you sure that is good? There is a relay in there some where. Does the motor run when you manually press the relay closed? If not look at the contacts. On a 30 year old motor they may be no good. Have you tried just hooking a line to the motor and checking if it runs?

The motor doesn't know hot from neutral. If you have only two leads you can hook them either way and it will run.
 
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Old 12-31-08, 08:55 PM
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I don't know if I make a oversight here but did you have push buttons like on / off or start / stop button ?

If so let us know there are few ways to get the correct connections on that and somecase the control transfomer can be bad once it go bad it will not fuction at all.

Merci,Marc
 
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Old 12-31-08, 09:27 PM
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Does pushing in the white button on the relay cause it to run?

 
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Old 12-31-08, 11:22 PM
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The black wire with the "faston" connector in the "LVC" needs to be insulated.

Are you sure the plug and receptacle are wired correctly and it has power? The green equipment conductor needs to be connected to the widest terminal, should be green colored. The white and black should be wired to their respective terminals, silver and brass.
 
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Old 12-31-08, 11:54 PM
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The green wire in the upper left corner of the LV box looks melted. Further down where it connects it looks burnt.

 
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Old 01-01-09, 06:51 AM
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Can you pull the wires out of the controller so we can tell where they go. Don't disconnect them just straighten them out so it'll be easier to tell where they are landed (especially the overload)
Also, on your transformer, what colors are being used and what the markings are on the wires. I can see a blue, white and brown but that's it.

This should be some pretty simple troubleshooting with this info and you have a multi meter.
 
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Old 01-02-09, 06:03 AM
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I manually pushed in the contactor with a stick and the motor started. Any idea where to troubleshoot next?
 
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Old 01-02-09, 07:05 AM
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The white wire that says "com" from the transformer. Is it going to L2 or the contactor coil? Also, the connections to the contactor coil, are they both on top or is one on the top and one on the bottom?

Or try this, push and hold the start button or put a temporary jumper in there and check for 24 volts on the contactor coil
 
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Old 01-02-09, 08:56 AM
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It's going to L2 per the diagram in my photos. What is the contactor coil?
 
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Old 01-02-09, 09:03 AM
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Originally Posted by oldhousenut View Post
It's going to L2 per the diagram in my photos. What is the contractor coil?
The contractor coil is the electromagnet on the relay (AKA contractor).
 
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