Please help with table saw motor

The diagram shown should be enough. It is very direct. The line cord has two functional conductors. The third is a ground, attaching to any convenient metal part of the motor. As a rule, 120V circuits are set up where L1 is the hot, or black wire. L2 is the neutral, or white wire. The Ground, or green wire goes to the motor frame. The important issue is with the dual voltage connections. T2 and T8 connecting to Terminal [4]. T3 and T5 connecting to Terminal [2]. Terminal [3] is left open, no connection.

The diagram doesn't show rated current. Converting to 120V will effectively double the current. The line cord should be a minimum of AWG14, preferably AWG12 or larger. I personally like long line cords and usually make them out of half of an "industrial" 25 ft extension cord. A fairly inexpensive source for molded plugs. . . The AWG wire size is usually printed(heat stamped) at regular intervals along the cable jacket.

The circuit supplying the saw must also be capable of handling the high current. The saw was wired for 240 volts for a reason. They usually come pre-wired from the factory for 120 volts unless they are commercial grade. You may do well to stick with the 240 volt wiring. Depending on the location among other factors, "borrowing" a tap from a dryer or range plug may provide a temporary outlet.

If there is a starter or contactor on board, the overload "heaters" will need changing also. Stash the old ones in a plastic bag taped inside the starter enclosure so they can be found easily if needed. That low of HP motor likely doesn't have any, but the previous owner may have put one on. If it is magnetic, the coil will need changing also.

.
 
I checked his wiring, hooked up neutral to L2, the motor won’t turn over. The blade jumps a bit but that’s it.
I have it in my truck.
Tomorrow I’ll ask you guys how to check the windings and start capacitor.
All I have is a Fluke T5-1000
Thank you
jeff
 
Bi11Hudson said:
The diagram shown should be enough for a twelve year old. It is very direct. The line cord has two functional conductors. The third is a ground, attaching to any convenient metal part of the motor. As a rule, 120V circuits are set up where L1 is the hot, or black wire. L2 is the neutral, or white wire. The Ground, or green wire goes to the motor frame. The important issue is with the dual voltage connections. T2 and T8 connecting to Terminal [4]. T3 and T5 connecting to Terminal [2]. Terminal [3] is left open, no connection.

The diagram doesn't show rated current. Converting to 120V will effectively double the current. The line cord should be a minimum of AWG14, preferably AWG12 or larger. I personally like long line cords and usually make them out of half of an "industrial" 25 ft extension cord. A fairly inexpensive source for molded plugs. . . The AWG wire size is usually printed(heat stamped) at regular intervals along the cable jacket.

The circuit supplying the saw must also be capable of handling the high current. The saw was wired for 240 volts for a reason. They usually come pre-wired from the factory for 120 volts unless they are commercial grade. You may do well to stick with the 240 volt wiring. Depending on the location among other factors, "borrowing" a tap from a dryer or range plug may provide a temporary outlet.

If there is a starter or contactor on board, the overload "heaters" will need changing also. Stash the old ones in a plastic bag taped inside the starter enclosure so they can be found easily if needed. That low of HP motor likely doesn't have any, but the previous owner may have put one on. If it is magnetic, the coil will need changing also.

.
Click to expand...
Oh, we have a problem.
This is an old house. He plugged it in yesterday and it ran then a fuse blew.
Yep, The light bulb screw in fuses are what blew.
Shoot.
No magnetic starter, just a 120v plug off the motor is how it came.
Would you please link or provide specs on the starter required?
I agree,, 220 gives the saw torque.
 
BGHansen said:
FYI from Google (current draw for a 1.5 hp motor). Might be some initial extra needed to get it going, think that is the starter capacitor's job.

Bruce


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Click to expand...
The term "horsepower" has been badly abused over the years. Sears used to sell woodworking routers that were rated at "3 HP" but required only 12 or 14 amps at 120 volts. I believe they were measuring just before the motor stalled.

My older Unisaw has a 1.5 horsepower motor. I mis-remembered the amp draw at 120 volts. It is only 19.2 but that is still well above what a typical 15 amp household circuit can supply. I run mine on 240 volts.

motor_tage_small.jpg

Craig
 
Hi Jeff- yeah that's a pretty heavy current draw for a 120 volt household circuit. Anything over 3/4 HP should be run on 240.
Motors draw much more current when starting than running. Blown fuse doesn't necessarily mean anything is wrong with the motor or house.
-Mark
 
Janderso said:
Oh, we have a problem.
This is an old house. He plugged it in yesterday and it ran then a fuse blew.
Yep, The light bulb screw in fuses are what blew.
Shoot.
No magnetic starter, just a 120v plug off the motor is how it came.
Would you please link or provide specs on the starter required?
I agree,, 220 gives the saw torque.
Click to expand...
Please DON'T just screw in a bigger fuse. That's a recipe to overheat the house wiring and cause a fire.

Use a motor rated starter sized for the amps the motor draws which depends on whether you go 120 or 240 volts. Your choice of magnetic or manual. Don't use a light switch--the contacts aren't designed to handle the current inrush and will eventually melt. Likely in the On position.

AIUI, thermal overload (heaters) are not required for a motor that is always attended. Thermal overload protection can help to prevent the motor from going up in smoke if overloaded. Your choice. Note, that many motors now have thermal protection built in: the red reset button.

All things being equal, the motor will perform exactly the same on 120 or 240 volts. In practise, it is easier to do the wiring right with 240 volts and so you might have a little less voltage sag. Doing it right with 120 volts means a circuit with heavy gauge wiring and an appropriate fuse or breaker. IOW, a new circuit. If you have to run a new circuit, just supply it with 240 volts.

Craig
 
If this motor is toast I would want to replace it with a 220v.
The amp rating is basically cut in half.
What about those converters, basically an up transformer?
Would that do?
I was not thinking the old house could not support a table saw.
This motor draws a lot of amps.
Just looking for ideas.
Thanks
 

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It seems there may be a couple of possibilities for what is wrong(?). If anything is. . . In the first case, an "Edison" base fuse means the house probably has 15 amp plugs and likely only a few (3-4) circuits. Essentially, such an electric system eliminates the use of such a powerful saw. If used, it would need to be fed from a 30 amp circuit. The first thing to look for is a "penny" behind the fuse. That is almost guaranteed a fire. If the saw took the fuse there probably isn't one.

There are several possibilities to get that feed. An air conditioner, an electric dryer, or a range plug can provide 120 volts on a temporary basis. Simply take one of the 240 volt lines and the neutral for 120 volts. An appliance pigtail with one line insulated will serve for a temporary line adapter. A range is usually 50 amps, AC or dryer is usually 30.

For a starter, I found a couple at Grizzly. The links are listed below, but usually they can be found at Home Depot or Lowe's. I didn't want to get into a serious search, too distracting. . .

www.grizzly.com

Magnetic Switch, Single-Phase, 220V Only, 3 HP, 21-25A

These professional grade magnetic switches protect against thermal overload and automatically shut down if power is interrupted, so equipment won’t start when circuits are turned back on. Single-phase, 220V only. 3 HP, 21-25 amp.
www.grizzly.com www.grizzly.com
www.grizzly.com

Single-Phase 110V 3 HP Mag Switch

<p>Professional-grade magnetic switches protect against thermal overload and automatically shut down if power is interrupted, so equipment won't start when circuits are turned back on. Single-Phase - 110V only. 3HP
www.grizzly.com www.grizzly.com

They have bigger ones but 3 HP sounded like enough for your machine.

There is a device that is a little larger than a light switch that still fits a single gang box. It is(was??) from Square D. It may be available from W W Grainger. There is a heater sold for individual motor size that basically makes it a manual starter. It prevents automatic restarts. . . You'll need the "Full Load Amps"(FLA) for the motor.

Starting the motor you might try to spin the blade. Use a scrap of 2X4 and stand to the side so when the blade snatches it out of your hand you're not close to the saw. That would confirm a start capacitor bad. Most likely there is an "open" wire somewhere when the voltage changes were being made.

Hope this helps. . .

.
 
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