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vfd on the big grizzly gun lathe?
- Thread starter skeetlee
- Start date
Lee I think you will find your two speed spindle motor is 4hp on high speed and 3 hp on low speed, this would be no trouble to run from a single vfd. If you ran the spindle motor on low speed you could use a 3hp vfd (as long as you don't switch the motor to high speed).
If you wanted to run the spindle motor on high then I would say a 8hp vfd would be what you would use, but it would pay to check with the vfd manufacturer.
I have a lathe that has a 5hp motor, I am using single phase into a 10hp vfd to run the 5hp motor with no problems, I imagine I could also run the coolant motor using the same vfd but since I fitted a coolant motor I fitted a single phase coolant motor.
One thing you have to do when fitting a vfd is wire it so your vfd feeds directly into the spindle motor. I fitted a vfd to a 3 phase lathe for a friend a while ago and used the forward/reverse contactors to switch the vfd forward reverse. A braking resistor is also good to wire in but if not set the vfd to "free run to a stop"
There are some easy ways to wire up a vfd that will work quite well, if you have a wiring diagram it would be pretty easy to work it out.
I have the same size lathe at home as the big Grizzly gunsmithing lathe, but the version I purchased only has 2 speeds in the headstock and uses a vfd and has a 5.5kw motor (7.5hp).
I fitted a vfd to the second lathe I owned and I'd never go back to owning a lathe without a vfd.
Vfd's are a lot quieter than a phase converter.
If you have any questions feel free to ask, can't say I'll have all the answers but may be of some help................Ian
If you wanted to run the spindle motor on high then I would say a 8hp vfd would be what you would use, but it would pay to check with the vfd manufacturer.
I have a lathe that has a 5hp motor, I am using single phase into a 10hp vfd to run the 5hp motor with no problems, I imagine I could also run the coolant motor using the same vfd but since I fitted a coolant motor I fitted a single phase coolant motor.
One thing you have to do when fitting a vfd is wire it so your vfd feeds directly into the spindle motor. I fitted a vfd to a 3 phase lathe for a friend a while ago and used the forward/reverse contactors to switch the vfd forward reverse. A braking resistor is also good to wire in but if not set the vfd to "free run to a stop"
There are some easy ways to wire up a vfd that will work quite well, if you have a wiring diagram it would be pretty easy to work it out.
I have the same size lathe at home as the big Grizzly gunsmithing lathe, but the version I purchased only has 2 speeds in the headstock and uses a vfd and has a 5.5kw motor (7.5hp).
I fitted a vfd to the second lathe I owned and I'd never go back to owning a lathe without a vfd.
Vfd's are a lot quieter than a phase converter.
If you have any questions feel free to ask, can't say I'll have all the answers but may be of some help................Ian
Butch Lambert
Active member
The 2 stopping resistors in mine are very inexpensive.
i found a 15hp 3 phase motor for free so i think a rfc is the way i am going to go. we have the two machines to power and we can do this for one money by using the roto phase. if the motor gets to noisy, or if by some chance i just plain dont like using a roto phase then maybe i will look deeper into a vfd. thanks men i always apprecite the info! lee