Motor to convert bandsaw to single phase.

[Richard Goodwin]

I am in the market for a used bandsaw with some re-saw capibility. There are not a lot of options in New Zealand, but I have found two. One is a fairly new Chinese or Taiwanese European style bandsaw with a 1.5Hp single phase motor and max cutting height of 228mm (bit over 9 inches). The other is an old cast iron frame unit which currently has a 3 phase motor. Would it be easy to fit a single phase 3hp motor, and if so, what sort would I need (4 pole or 2 pole etc)? What would people recommend, newer frame type saw or old cast iron frame?

[Larry Edgerton]

If you want the old cast iron unit, you do not have to change the motor, in fact I would not as those old motors have a lot of mass that is a huge benifit. Instead I would get a phase converter or a VFD, more likely the VFD for your purposes. They can creat heat in old motors but only when used as a speed control, if run at normal speed they are fine as it was explained to me.

http://www.factorymation.com/s.nl/it.A/id.193/.f?category=30

[Mike Henderson]

You don't give the prices of the two units. A new motor will cost you perhaps $200US (bought in the USA, your prices may be different). The other thing to be concerned with is the mounting of the motor. Some old bandsaws used direct drive motors, which could be a special mount and would make the motor difficult to find and much more expensive.

Regarding 2 or 4 pole, a two pole motor will operate at about 3450RPM (60Hz) or about 2875RPM (50Hz), while a four pole motor will operate at 1725RPM (60Hz) or about 1438RPM (50Hz). For a given HP, the two pole motor will be a bit smaller (and probably a bit less expensive) and you can use pulleys to get the same effective speed out of it (assuming its not a direct drive motor).

If it's not a direct drive motor, a 56 frame motor will probably be what you'll be looking for since they're the most common.

The other approach is to purchase a VFD and use that to drive the 3 phase motor. This may be the cheapest and best approach if the old bandsaw is in good shape.

Mike

[John Bailey]

I just went through the same situation a few months ago. I bought a cast frame Oliver 192 with a 3-phase motor. I had a lot of apprehension concerning using a Variable Frequency Drive. I should not have worried. It has worked great. There are other benefits besides the conversion to 3 phase. One is that you can dial down the frequency when you are aligning the blade or cutting metal. Another is that the VFD works as a brake and slows down the wheel more quickly than normal. There is an adjustment for this on mine. I would see if FactoryMation can be of help to you. I don't know if they can ship to New Zealand, but it's worth a try. I bought the 2 hp FM50 model for $145 USD. If I were to do it again I'd get the NEMA model because I worry about dust. However, many have gone with the regular model with great success.

By the way, I would go with the cast iron band saw. It would be good if you could fill us in with the details of that saw.

John

[Richard Goodwin]

Thanks for the helpful replies. In the end I didn't purchase the bandsaw I was looking at. It was just too big. However I am still on the lookout, and the VFD may be a good option if I find a suitable saw with a 3 phase motor. Again thanks to those who took the time to reply.