Replies

1. 
   highfigh | Sep 25, 2005 05:28am | #1

   I assume you now have 220V in the shop, right? If you don't, the motor will not work. Residential 220V uses 2 110V lines of opposite phase, a ground and no neutral, as opposed to 110V, which uses a hot, a neutral and a ground. The most recent electrical code now calls the neutral the "grounding lead" and the ground is now the "grounded lead".

   Don't try to run the saw unless you have 220V. You could get a different motor but your electrical service will probably need to be upgraded in order for the same HP to be present.

   "I cut this piece four times and it's still too short."
1. 
   Creaker | Sep 25, 2005 06:03am | #2

   I do have 220v to the shop. I even checked to verify that I was getting 220v at the socket. All seems to be hooked up correctly. I checked the motor to make sure it was just a single phase motor and it is.

   I know large, 3 hp motors like this have capacitors and I wonder if this may be the problem. Do you know how to check out a capacitor? Creaker

1. 
   highfigh | Sep 25, 2005 06:24am | #3

   If you have a digital multi-meter, set it to resistance and with the capacitor removed, test it for continuity. There are usually 2 to 4 tabs on these caps, so you'll need to test each pair with the red lead on one and the black lead on the other, then reverse the leads. If you see continuity in both directions, the cap is bad. If there's a motor repair/rebuilder in your area, they can test the motor fully, in ways most people aren't equipped. They can also advise on why it isn't working.
   "I cut this piece four times and it's still too short."

1. 
   maddog3 | Sep 25, 2005 03:04pm | #4

   If I could add something, when you are done checking your capacitor, use a screwdriver or similar tool to short the terminals you have just tested, before you try to re-install it
   If the cap is good, you could get a REAL jolt.do you have the right size breaker? how about the cord on the saw, is it frayed or brittle?It sounds like something is shorted to the frame somewherebefore you tear the saw apart , if you have a continuity tester, test to see if you have continuity from the plug to the frame of the saw."

1. 
   highfigh | Sep 25, 2005 05:43pm | #5

   Actually, the cap should be discharged before testing. The stored charge could damage the meter and I should have mentioned this in my other post. It would be a good jolt, but not particularly high voltage. It's just that the terminals are pretty close together and could provide a bad enough burn at the site of contact.If there is continuity from the cord to the saw frame on something other than the ground wire and the cord is OK, the motor field is probably shorted to the case and will need repair. As I said before, there should be a motor repair shop near you and they can fix it pretty easily. If the motor, switch and any associated wiring can be removed from the saw before taking it in, they can test it as an assembly."I cut this piece four times and it's still too short."

   Edited 9/25/2005 10:46 am ET by highfigh

2. 
   maddog3 | Sep 25, 2005 06:10pm | #6

   ....good points, I was trying to think of other things that could be looked at before creaker pulls the motor"

2. 
   h12721 | Sep 25, 2005 11:01pm | #7

   Creaker, I have a 50 year old Unisaw and that Motor does not have a capacitor .

   3HP and weights a ton  also slower turning than the new ones.but rpm on the blade is the same, via the pulleys. Check the switch or get someone who knows how to check motors.  Like I said no caps and no centrifugal switch. So must be wiring or a bummer.

   Hilmar

1. 
   Creaker | Sep 25, 2005 11:08pm | #8

   Thank you all for your suggestions. They are the type I was hoping for. I will go out there right now and see what can be done. Creaker

1. 
   Irv | Sep 26, 2005 01:55am | #9

   Does your Unisaw have a power control box between the motor and the 220 power line that plugs into the outlet?  The motor cord and the switch cord plug into the control box and the control box cord plugs into the electrical outlet. My saw has such a contol box whose function is to prevent unintentional start-ups after power is interrupted (say the motor circuit breaker opens, or your electric service is interrupted) and then goes back on and the saw switch has not been set to off.  This box has a relay in it that could go bad. There may also be an overcurrent sensor circuit breaker in it. If you have such a control box, remove it from the circuit (bypass it) temporarily to see if it is this box or the saw that is the problem.

   Good Luck.

   Edited 9/25/2005 6:59 pm ET by Irv

   Edited 9/25/2005 7:01 pm ET by Irv

2. 
   h12721 | Sep 26, 2005 04:54am | #10

   Irv, mine did not have such a controller. It just had a regular Kitchen, Living room     toggle switch, except heavy duty and for the big Amps. Do not know about Creaker's

   But I have no problems with my saw,just mention what there where 50 years ago

   Hilmar

   Edited 9/25/2005 10:00 pm ET by h12721

2. 
   BarryO | Sep 26, 2005 06:46am | #11

   The most recent electrical code now calls the neutral the "grounding lead" and the ground is now the "grounded lead".

   You have it backwards.  What laymen colloquially refer to as the "neutral" lead in single-phase, 2-pole, 120V/240V residential electrical service is referred to by electricians as the "grounded lead" or "grounded conductor".  The NEC has always said this.  This is the white or grey branch circuit conductor that is tied to the Service ground back at the main panel.

   The term "neutral" is properly used in 3-phase applications.

   The green or bare "ground" lead is referred to as the "equipment grounding conductor" in the Code, since its purpose is to ground electrally-powered utilization equipment, and provide a safe return path for fault currents, with a low enough impedance so that breakers will trip.

1. 
   highfigh | Sep 26, 2005 10:09am | #12

   You're right, sorry for any confusion.
   "I cut this piece four times and it's still too short."