[Newbie] VFD vs New Motor...110 vs 220 input

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agshooter

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Howdy,
I recently picked up a Clausing 12x36 built in 1954. It has a 3 ph 3/4 hp motor running 1800 RPM.

I see a couple of options to get the lathe up and running in my house. I have a 200 amp subpanel set up for my HVAC. HVAC is only using 70 amps, so I can add a couple more breakers for machinery. I just need to add the breakers and run wire to the "machine shop room." So this leaves me with option to run 220 or 110 or both.

1) Use a VFD to convert single phase house power to 3 phase for the motor. If I go this route, better to get a 1HP VFD with 110 or 220 input?

2) Replace the motor with a single phase motor like this https://www.grizzly.com/products/Gr...HP-Single-Phase-1725-RPM-TEFC-110V-220V/G2530 and wire it for 110 or 220.

I am thinking no matter what I do, wiring the shop for 220 would be best because that would decreased the amp draw on the subpanel and leave more room for other machines if needed.
 
I would stick to 3 phase motors. They are simpler and easier to adjust speed on with VFDs. They are also quite reasonably priced now.

For running new wire, run 220. You need less current for the same HP, so you can use smaller cheaper wire. You can also pull 110V out of it so long as you pull 4 wire runs for the 220. If you have to do a lot to get wire over there, consider conduit. Then you can pull new wire anytime later as needed. Another option, which is how I went, is to run a 100A subpanel in the shop. Now it's easy to add circuits. And I have the breakers local if I need to flip them for some reason or another.
 
Concur with the above. I have a writeup on the Clausing 5914 VFD conversion in the Clausing section which should be similar to what you would need.
 
Any reason I should not go with this VFD?
www.vfds.com

1HP 230V Galt Electric G200 VFD, Inverter, AC Drive G22S000042UL-01

Drive DetailsManufacturerGalt ElectricSeriesG200ModelG22S000042UL01ConditionNew3 Year Manufacturer WarrantyConstant/Variable TorqueCT/VTHorsepower?HO: 1 HPMaximum Amps?HO: 4.2 AInput1-Phase200-240V 50Hz/60HzOutput3-Phase200-240V 50Hz/60HzEnclosure RatingIP20Features4 Common Digital Inputs 1 High-spe
www.vfds.com www.vfds.com
 
I’ve read you should go with a VFD rated for 1.5-2x the hp of the motor, so I should look for a 1.5hp VFD?
 
I've seen posts about that, but I have never seen it from an authoritative source. It's always "someone". The components are rated based on voltage and current, so as long as you're there or under, I see no reason to de-rate the VFD.

My belt grinder is a 2HP motor with a 2HP VFD, no issues.

The Bridgeport feed motor is 1/8HP and also has a 2HP VFD, works fine. :)
 
Derating of 1.5 to 2 is used when you are using a 3 phase input VFD and want to use it with a single phase input. If a VFD is designed for single phase input there is no derating. VFD's often are sized in increments that may not match your specific motor, you would round up to the next size. The other rating to check when buying VFD's is the rated output amperage, not only the Hp, and also the type of load that it will be running. So you will often see three or more different ratings, one for variable torque, another for constant torque light/regular duty and then for high duty constant torque. On a lathe, I usually plan on setting them up under constant torque heavy duty load. There is also some derating on some models for the higher carrier frequencies. So would go with a 1 hp VFD in your case, the Galt model above is single phase input and rated at 4.2A output current under constant torque. There are other factors as to programming parameters and also in cases where you need quick braking, support for an external braking resistor. The Galt does support a braking resistor, but only has 4 inputs, depending on what you want it to do this may be limiting.
 
mksj said:
Derating of 1.5 to 2 is used when you are using a 3 phase input VFD and want to use it with a single phase input. If a VFD is designed for single phase input there is no derating. VFD's often are sized in increments that may not match your specific motor, you would round up to the next size. The other rating to check when buying VFD's is the rated output amperage, not only the Hp, and also the type of load that it will be running. So you will often see three or more different ratings, one for variable torque, another for constant torque light/regular duty and then for high duty constant torque. On a lathe, I usually plan on setting them up under constant torque heavy duty load. There is also some derating on some models for the higher carrier frequencies. So would go with a 1 hp VFD in your case, the Galt model above is single phase input and rated at 4.2A output current under constant torque. There are other factors as to programming parameters and also in cases where you need quick braking, support for an external braking resistor. The Galt does support a braking resistor, but only has 4 inputs, depending on what you want it to do this may be limiting.
Click to expand...

My current motor is rated at 2 amp, so I think the 4.5 amp Galt will be good. I don't know what I don't know when it comes to inputs and its limitations. Care to elaborate?
At minimum I need to be able to use the 3 way switch (forward, off, reverse). The variable speed is a bonus for dialing in speeds, but I really dont mind moving the belt around. What other options are you referring to?
 
If you use a VFD, you will not use the existing 3 way switch to control those functions. All motor control is done through the
VFD itself. Existing controls are bypassed.
 
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