Professionals and Amateurs Together

Dying Motor

Question

I have a 14″ Jet bandsaw with a slowly dying motor (I need to give it a spin to get it to turn on). Can I replace it with a higher horsepower motor? What’s the limit on h.p. for an existing tool? How do I “spec” the motor if I buy it from a catalog?—Anon

Answer

Bob Couch replies: My first question would be, do you have the riser block on the Jet 14″? If so, you could upgrade to a 1.5 hp motor. Otherwise, I would stick with the same horse power. I have a Jet 14″ without the riser block and the 1 hp works just fine.

As far as the replacement goes, I would search online. Granger is one good source. You would be looking for a 1 hp induction motor and you need to make sure you match are the following specs—110 volt or 110/220 volt single phase, frame spec. (mounting bracket) 56C is common, enclosed case is a nice to have as there is less danger of a spark starting a fire.

Peter James replies: Your existing motor problem is caused by either a bad starting capacitor or dirty or sticking starter circuit contacts. The capacitor can be replaced cheaply. They are available on eBay for less than $10. The specifications are printed on the one on your motor. The contacts are inside the motor and you will have to disassemble it to clean them. As for a replacement motor, for a 14″ bandsaw a 1-1/2 hp motor would be about the maximum you should need. Your existing motor tag has a “frame” number on it. Something like a 56 or 56H. This frame number specifies the motor physical size including the shaft size and the mounting plate hole locations. Get a motor with the same frame number and it should bolt right in. Up top about 1 1/2 hp can run on a 110V, 20 amp circuit. If you go to a 220V motor you may need to replace the off/on switch so that you can switch both hot wires in the circuit.

Richard Oedel replies: The motor not starting is common in dusty environments, and can be due to dust between the contacts that control the startup winding and are located in the end of the motor. There are actually two windings in a single phase motor, and they work differently. Both windings are used in startup and the second when it is running. The starter winding is the one that is not working for you. Take off the end of the motor where the wires enter (you don’t need to disassemble much, since this is just a set of contacts) and clean out the area, sanding the contacts as needed with 400 grit sandpaper. If it still doesn’t work, the capacitor may be bad (that lump on the side of the motor). Take it out and take it to your local electric supply shop for a replacement.

Bruce Wedlock replies: You can put as big a motor on your bandsaw as can be mechanically mounted. A higher horsepower will prevent stalling when resawing large pieces. I replaced my 1/2 hp motor with a 2 hp motor on my Delta 14″, and now slice through 10″ of hardwood with no problem. The only spec of concern is the rpm. The new motor should match the old motor rpm so the blade speed remains correct. Of course the mounting frame of the motor needs to accommodate your saw, and more money buys a better quality motor. I got my 2 hp used for $25.

Bob Oswald replies: There’s little point in adding more horsepower to this saw. It was designed to run with what it has and the small blades used on a 14″ saw should cut just fine. On the other hand, if you’re doing heavy resawing, more power could keep it from bogging down. However, it sounds like this motor might benefit from repair. It sounds like the starting circuit (capacitor or starting switch) isn’t working and a motor repair shop in your area might be able to fix it cheaply.

Tags: Motors