Table Saw Motor Current Draw

[Garrick Neal]

Hello Everyone

I've been reading a lot of Sawmill Creek forums for several years, but this is the first time I'm posting.

The reason is my table saw motor has suddenly started drawing more current than I have available, and I need some help.

It's a 63 year old Walker-Turner, which has served me well for 20 years. It is a 1 HP, 110 Volt, 15.4 Amp brute of a motor. My breakers are only 15 amps, and I have tripped the breaker many times before, but only when pushing thick chunks of wood through the blade. Now it suddenly won't get up speed before tripping the breaker.

I plugged it in to another breaker circuit and had the same problem. I also replaced the switch and the starting capacitor, neither of which made a difference. I removed and blew out the motor, and it bench tested fine (It takes 2 minutes to wind down with load on it), but would not get up to speed once it was again attached to the saw arbour.

My speculation is that sawdust caused some damage to the motor, and it is now requiring more current to start. The start capacitor is smaller than the casing it is in, and even though I replaced it with an identical capacitor, am wondering if the capacitor had previously been replaced with one that may be too small. I am considering installing a 20 amp breaker, to overcome the problem. But I would like some advise before proceeding .

Garrick

[Robert Mills]

a 15.4 amp tool shouldn't be on a 15 amp breaker anyway.

[Anthony Whitesell]

If it has start and run capacitors, I would check the centrifgual switches perhaps they are not sliding as well as they used to in their younger days.

[Garrick Neal]

I don't think it has a run capacitor. There is just the one capacitor on the outside of the motor casing.

[Rod Sheridan]

A failed start switch, start capacitor or open start winding is where I would begin troubleshooting.

The start switch can be broken, stuck, or jammed open with sawdust. Nothing a careful dis-assembly, inspection and cleaning won't cure.

Regards, Rod.

[Josiah Bartlett]

Check the arbor bearing for damage and try to start the motor with the belt detached from the motor. It could be that the motor is fine but the saw has an issue..

[Don Jarvie]

Change out the breaker 1st to 20amp and give it a try. Make sure you are using 12 g wire on the 20 amp breaker.

Most likely the start load to too much for the breaker to handle. If you can wire you motor for 220 (switch the wires around) and install a double 20 amp breaker it would be better. You would have more than enough juice to run the motor.

If you are going to keep the saw you might want to consider getting a larger HP motor, 2 to 3 hp. I run my WT with a 3 hp motor and it cuts through anything.

Don

[Rick Fisher]

I have seen breakers get old and sloppy.. funny.. not until recently.. only heard of it before that ..

Its more likely one of the issues Rod mentioned, but if the motor is fine, try a different circuit..

[Trent Shirley]

No doubt you should be on a 20 amp circuit but since this is a new issue on your 15 amp circuit it does mean the motor is pulling more current than it had previously unless both circuits you tried have weak breakers that need replacing.
Before switching to a 20 amp circuit to provide more power you definitely want to determine what the issue with the motor is because providing more power to keep it going would only mask a problem that may get worse.

As Josiah suggested, the problem could be elsewhere than the motor, you need to know how the arbor is working. If the bearings in the arbor were going bad it could be providing extra resistance bogging down the motor at startup.

[Garrick Neal]

Thanks for all the suggestions. I am almost certain the problem lies within the motor. I've checked or replaced almost everything else. The saw spins fine without the motor attached, but of course, only as fast as I can get it moving by hand. There are 3 short belts which do provide a lot of resistance, which I believe is why when the motor is installed, is enough load that in it's present condition, that it draws too much current.

I do have one 220 volt outlet in the shop, but it is dedicated to the dust collector. I hadn't thought about the possible damage a 20 amp circuit could do to the motor. The 15 amp breaker may be preventing even more damage to it. BTW (which means "by the way"), the saw used to have a fused circuit breaker switch, which I replaced several years ago... I hope that hasn't caused some or all of the problem.

Please correct me if I'm wrong, but I think my next step is to remove the motor again (a 3 hour process, including reinstallation), and take it apart. If I am unable to get it running with my limited electric motor knowledge, I wll have to decide whether to replace it or have it repaired. If I do replace it, I will likely have to go for another 220 volt circuit in the shop.

Don... What model is your Walker-Turner. This one is a TA950B. It's on the Vintage Machinery site. http://vintagemachinery.org/photoind...l.aspx?id=8811

Thanks again
Garrick

[Don Jarvie]

Garrick, I have the 1180B which is the full size cabinet saw. I run 2 belts with a 3hp motor. 2 belts is plently.

I see you have the Driver Line WT motor. This may be a good question for the guys at OWWM since that motor is pretty popular.

You can open it up like it has been suggested and clean the centrifical switch. A light sanding with 600 on the dots can make all the difference in the world. Also, when you take it out see if it has any problems running while its on the bench.

A good cleaning is probably all it needs. If the bearings are bad you can replace them while you have it apart.

Don

[Curt Harms]

If it worked okay before and doesn't work okay now, something changed. Either the motor or the breaker is developing issues. I had a similar problem years ago with a newly installed C.B. The borgs had what appeared to be the same breaker but one store was significantly cheaper than the other. Brought the cheaper home, installed it, turned the machine on and "POP" it tripped right off the bat. Reset and the same thing happened. The amp rating was adequate for the load. I took that one back and bought the more expensive one. it's been fine for 15+ years. I took from this that some C.B.s are designed to tolerate motor start loads better than others.

[Rich Engelhardt]

It is a 1 HP, 110 Volt, 15.4 Amp brute of a motor. My breakers are only 15 amps, and I have tripped the breaker many times before

Why are you running a 15.4amp [i]anything[/] on a 15 amp breaker?

IMHO - that's just begging for trouble or a fire.