Would a VFD play well with a bandsaw, including the blade welder?

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fvdbergh

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I am currently looking at a deal on a used band saw. It is a 3 phase 380V saw with a 850W motor (1.1 hp?), and the blade welder is rated at 2.4 kVA.
I have single-phase 220V power, but the increase in utility charges for 3 phase service does not seem worth it.

Now I have some questions:
1. Can I just use a 2.2 kW VFD (seems to be a popular size) to power the motor and blade welder? Will a blade welder be a load that is compatible with a VFD that is nominally intended to drive inductive loads? Fortunately it is a metal saw, so I will not have to use the VFD to slow the motor or anything.
2. Maybe I can run the motor on single phase (will only really see when I have the saw in hand), and I don't know much about 3 phase motors. Or maybe I can install a single-phase motor, which seems a little cheaper than the VFD. So what do the blade welder circuits look like? Just a transformer? Maybe they only use a single-phase step- down transformer? That way I can convert the whole saw to single phase?

Since I have never seen one of these in person, any insights or suggestions would be greatly appreciated.
 
The blade welder may not play well with the VFD due to the inductive kick from the transformer when it shuts off. If you were to turn on and off the blade welder with the VFD you might be OK but you may have to bypass the blade welder's timer if it has one.
2.4 kilowatt is a heavy load, much more than the motor. If you could rewire the blade welder transformer to run directly off the 220 volt line I would.
-Mark
 
You have a couple of problems here. The machine is currently wired for 380V, 3 phase. So a 220V single phase circuit will not supply enough voltage to run the machine even if you install a VFD. Many 380V motors can be wired for 220V in which case a VFD could be made to work with the motor. You need to look at the data plate on the motor.

The welder transformer is single phase, and may be rewirable to 220V. Again you would have to look on the data plate on the welder or transformer. Under no condition do you want to connect the VFD to the welder, you will destroy the VFD.
 
if the motor can be retapped, the VFD is a viable solution- even if it is used at 60HZ alone.
as stated, the weld, or any other transformer, can't be hooked up to the output of the VFD
 
I have heard of some step-up transformer to motor setups being successfully driven from a VFD, but I wouldn't try running a blade welder transformer, too much likelihood of blowing up the VFD output stage
 
Thank you very much for all the replies.

I guess I will have to be patient, and wait for the machine first to see what I am dealing with.
No chips on the first day :(
 
I'm using a blade welder that was removed from a 3 phase Do-All band saw. It doesn't use 3-phase power. It is 220v single phase. In the original saw, it was only wired to two legs of the 3-phase supply. So, you might not need 3-phase for your welder, but you would have to wire it separately. Like others have said, the voltage it too high for a 220v VFD, but maybe the motor can be setup for 220v 3-phase. Or, the motor can be replaced.

Ted
 
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