Thread: Wood lsthe VFD conversion

Picked up an the old 3ph woodfast lathe sometime back and its finally found some space in the shed.
Fitted a vfd.
What i like about this VFD is that it can convert hertz to theoretical RPM for the display with some simple programming of theoretical driven shaft rpm.
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Just need to fit perspex cover and black all the areas one doesnt want to see.eg wiring

The old wood fasts are nice bits of gear.
What happens if you need to change the pulleys?

Originally Posted by BobL

The old wood fasts are nice bits of gear.
What happens if you need to change the pulleys?

Hoping I dont have to change speeds via pulley. At 110hz the spindle gets up to calculated 3619rpm.
Inverter has sensorless vector so hoping it will have enough torque for turning at lower speeds.

Any lower will only be for polishing anyways.

But if I need to get more torque I change pulley ratio and adjust vfd to suit theoretical speed.

Originally Posted by eskimo

Hoping I dont have to change speeds via pulley. At 110hz the spindle gets up to calculated 3619rpm.

But if I need to get more torque I change pulley ratio and adjust vfd to suit theoretical speed.

There's a general rule of thumb that says multiply the rpm by the diameter of the wood (in inches) and the result should be in the range of 6000 to 9000. If the wood is out of balance will have to start at a lower speed until it is evened up.
You can work out your pulley ratios based on what you are likely to turn.

Originally Posted by tony_A

There's a general rule of thumb that says multiply the rpm by the diameter of the wood (in inches) and the result should be in the range of 6000 to 9000. If the wood is out of balance will have to start at a lower speed until it is evened up.
You can work out your pulley ratios based on what you are likely to turn.

yep done all that.

I have used 110mm drive/95mm driven pulleys so only need to go to 110hz to get the 3600rpm

For more torque I could have gone 95mm drive/110driven but hz will be around 150...I have opted for lower hz but can change if needed.
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Originally Posted by eskimo

yep done all that.

I have used 110mm drive/95mm driven pulleys so only need to go to 11ohz to get the 3600rpm

For more torque I could have gone 95mm drive/110driven but hz will be around 150...I have opted for lower hz but can change if needed.
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Looks like you've got it all sorted.