I bought a Carbatec Vertical Bandsaw ( 345C )recently and could not justify the cost I variable speed model as it cost me $1800 as it was.
I am not thinking of modifying it so I can cut differnt metals as well as wood.

My first thought was to use a DC motor and speed control due to DC motors having very good lower speed torque. (They are expensive and would take alot of moding to fit. Also ,none S/H locally )

But then I thought if I could keep the motor speed closer to 50Hz at metal cutting speeds, then a 3 phase motor would have enough torque.

I could do this by fitting a 4 pole 3 phase motor and VFD and then run it at higher frequencies for cutting wood.

With a 2 pole motor, presently the blade speed is 880m/min.
If I fitted a 4 pole 3 phase motor, that would reduce to 440m/min ( still a bit fast?)

So if 440m/min was when running at 50Hz,

Getting back to 880m/min ( not really required, I think ) I would need 100Hz.
300 m/min would be 34 Hz, and
200 m/min would be 22 Hz.


I'm thinking that would probably work OK. 22Hz is not *too* slow, I think. I may not even need to go that slow...not sure yet.

Will try to get a 3 phase 4 pole motor that bolts straight up and get a cheap VFD off Ebay. Shouldn't be too expensive.

Steve

Cutting Speed Calcs.jpg
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