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dgr68 01-02-2009 08:57 AM

Motor control wiring problem
Hi All: I have a thread in the tools forum titled "unisaw wiring problem" that I need help with. I have a table saw motor that is controlled by a lvc and we cannot get the motor to turn on with the push button. I manually pushed in the contactor and the motor turned on. I tested the leads out of the transformer and they read 24v. Any help you can lend is appreciated.

The photos are here:

And the original post is here:

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!!

Steelhead 01-02-2009 09:29 AM

When you push the start button do you get 24V at the coil of the motor contactor?

wirenut1110 01-02-2009 10:15 AM

This guy has posted in another forum but never answers the questions you ask him. I've asked the same question and he doesn't respond. His transformer common goes the the overloads (so it looks like) and either it needs to be reset or is defective.

Steelhead 01-02-2009 10:28 AM

Thanks WireNut, I guess we'll see what happens. The ball is in his court. If he wants help he should answer the questions that are asked of him!

dgr68 01-02-2009 11:48 AM

Wirenut- No offense intended I missed your first questions and answered the second. A lot of people are asking questions and I'm trying to digest it all which is not easy as a novice. In any event, I appreciate the help and interest. I can take another picture of the lvc with the wires out. The transformer has 2 brown leads coming out(one connects to the hot in the on off switch, the other to the overload), a white com that goes to the contactor and 4 different leads labeled(115,200,,230,460) Steelhead- when I push the start button nothing happens. I have tested the two brown leads and they show 30v. The L1/L2 show 140v. Any ideas?

wirenut1110 01-02-2009 11:54 AM

Push and hold the start button, check for 24 volts at terminal#3 on the contactor and the red wire on the overload relay. If you get 24 volts then your contactor coil is bad. If not check the overload for continuity, if it's good then you have an issue with your start/stop. If there's no continuity then push the reset button and see if it clears.

micromind 01-02-2009 01:04 PM

This was posted in the 'tools' section, but it disappeared about 10 minutes after I wrote a detailed troubleshooting sequence.

Guess the computer didn't like my post!


P.S. Apparently, the reason for the disappearance is because the post was being moved to the electrical section. Obviously, I spoke too soon!

Steelhead 01-02-2009 01:17 PM

I agree with wirenut. Try that and see what happens. Keep us informed.

dgr68 01-04-2009 05:13 PM

The problem is the overload. I bypassed the control loop on it with a jumper and the contactor engaged and stayed engaged when I pushed the start. Question is- what do I do now? There doesn't seem to be any way to push the red stick so I don't think it is tripped. Is there a fuse in it?

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