VFD a good choice to run a small turret lathe?

Not sure I know what a VFD does but seems it outputs 3ph from 1ph input? If so it'll be way more efficient that the 20 and 30hp RPC's I run, right? I see 3hp listed on a sales page for this model lathe (Jet).

As a phase converter it may be okay but I would be careful using one to vary the speed on a Jet lathe- the low quality electrical systems on these machines may burn up- not all motors are VFD rated.

MARK07747 said:

As a phase converter it may be okay but I would be careful using one to vary the speed on a Jet lathe- the low quality electrical systems on these machines may burn up- not all motors are VFD rated.

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I would use it solely as a power supply and use the continue to use the onboard 4spd trans if I go that way.

It may not matter a lot if it is used to vary speeds or not. Once you use a VFD, you have the same sort of "pulse width modulated" output whether you vary speed or not.

If the electrics cannot handle it, they probably will not like it at any speed.

Also, you will have to start and stop the motor via the VFD controls. The VFD cannot handle the starting surge unless the VFD is much larger in capability than the motor, usually rated at least for 5 x the motor current as continuous output. Otherwise it will "fault" on overcurrent, and just shut down.

Some VFDs can be set to not shut down, but to limit current and keep driving the load. That "may be" enough to get the motor and workpiece spinning without a stall. Lathes with a clutch are much better for that, as they start with minimal load.

A VFD is a perfect choice to power a 3phase motor from single phase.
In the early days, VFDs had very fast switching edge rates that had very large voltage spikes on the motor connections. These could break through the insulation on the motor wiring resulting in winding shorts to chassis. But this is no longer a problem as the rise and fall time is part of the design of the transistors used.
Do not buy a cheap VFD as in the ones from China are based on an antiquated design, using poor quality components. An example is Huangang.
I would recommend anything but.
Good price for quality TECO brand from dealerselectric.com
I've had a RPC, of home spun, never liked that I had to start it, before starting the machine. And it was a noisy motor wasting power. They makes sense for very large Horsepower loads, but for 3HP range a VFD is the good solution.

While I now have shop wide three phase, I have run a lathe and mill for years with VFD's- excellent trouble free service.
I am using the Hitachi WJ200 series.
I have ten second ramp ups set on both machines which gives some time to ease load and is a safety aid.

Trboatworks said:

While I now have shop wide three phase, I have run a lathe and mill for years with VFD's- excellent trouble free service.
I am using the Hitachi WJ200 series.
I have ten second ramp ups set on both machines which gives some time to ease load and is a safety aid.

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I think the concern is contactors and switching the motor on and off while the VFD is at full power.

If you are electrically savvy you can power the control circuitry to the single phase input and have all functions behave normally by linking the control buttons to the VFD. This gives the advantage of still having speed control and the VFD ramp.