I would probably recommend a single phase input 240V 5Hp drive as a first choice for several reasons. First they are available and they are less expensive than something like a 10Hp 3 phase input VFD drive like a Hitachi WJ200-075LF. This is the most likely the size you would need for a 3 Phase input drive that is derated for single phase use. The usual derating factor is to take the VFD output and divide by ~1.7, you can use a DC choke and maybe get this down to 1.5, but the total cost will be even more. The other predominate factor is that even though you are using the VFD in a derated mode for single phase input, the power input side to the VFD has to be rated for the full VFD rating, so 10Hp, or 7.5KW. Game changer when you get into the wiring fusing and breaker needed to support this size of a VFD.
My first recommendation would be a Yaskawa drive, they are a highly rated drive and used widely in many industrial machines. Almost every factory 3-5Hp single phase input VFD lathe or mill comes with a Yaskawa drive. It is also the least expensive. I would buy it from an authorized dealer so you have support and a warranty. Yaskawa, CIMR-VUBA0018FAA, 5HP, 1-Phase, 200-240V (Input), NEMA 1 Enclosure, Variable Frequency Drive, 4.2KW, 17.5A
https://motorsandcontrol.com/yaskaw...ut-nema-1-enclosure-variable-frequency-drive/
The Polyspede line has been replaced, the spedestar is not UL approved for what it is worth. The Polyspede equivalent in a newer model is the Invertek Drives
The VFD drive is the E3 model ODE-3-320153-1042 INput:240VAC, Single Phase Output: 5 HP, 240VAC, Three Phase 4kW, 15.3A
https://www.driveswarehouse.com/ode-3-320153-1042
http://www.invertekdrives.com/variable-speed-drives/optidrive-e3/
I have purchased drives from both of the above vendors, I would call them and ask them what they recommend for your application. I have a Yaskawa drive in my mill, the Hitachi on my lathe, up to 3Hp with single phase input, I would recommend either. Invertek Drives are somewhat new, I have no experience with them, but speak to Drives Warehouse. I would go with the Yaskawa, CIMR-VUBA0018FAA as it is more widely supported and more widely used. I also believe this is what Eisen uses in the VFD variable speed lathes/mills
All these VFDs take a bit of work to get programmed and dialed in, the manuals can be a bit daunting. The other factor is you need to know how to wire the VFD into the machine controls, I strongly do not advise connecting the VFD inputs directly to the spindle switch for the direction controls, there are just too many things that can happen on a lathe with severe consequences. It is possible to strip out the high voltage wiring to the forawrd and reverse contactors and use them to switch the forward/reverse VFD inputs. All the other controls will work the same, the motor is directly connected to the VFD. I also like to add a few other safety features. The other component is that your machine comes with a manual brake, so if used you need to switch out the current brake limit switch for a dual pole, one side is wired as before (usually a NC that goes open when the brake is applied), the other pole you use a NO contact and is wired to a VFD input that gives the freewheel command (no electronic braking when the manual foot brake is engaged). It is not a simple drop in job. You could also go with an RPC which may be less expensive and much simpler to install.
My first recommendation would be a Yaskawa drive, they are a highly rated drive and used widely in many industrial machines. Almost every factory 3-5Hp single phase input VFD lathe or mill comes with a Yaskawa drive. It is also the least expensive. I would buy it from an authorized dealer so you have support and a warranty. Yaskawa, CIMR-VUBA0018FAA, 5HP, 1-Phase, 200-240V (Input), NEMA 1 Enclosure, Variable Frequency Drive, 4.2KW, 17.5A
https://motorsandcontrol.com/yaskaw...ut-nema-1-enclosure-variable-frequency-drive/
The Polyspede line has been replaced, the spedestar is not UL approved for what it is worth. The Polyspede equivalent in a newer model is the Invertek Drives
The VFD drive is the E3 model ODE-3-320153-1042 INput:240VAC, Single Phase Output: 5 HP, 240VAC, Three Phase 4kW, 15.3A
https://www.driveswarehouse.com/ode-3-320153-1042
http://www.invertekdrives.com/variable-speed-drives/optidrive-e3/
I have purchased drives from both of the above vendors, I would call them and ask them what they recommend for your application. I have a Yaskawa drive in my mill, the Hitachi on my lathe, up to 3Hp with single phase input, I would recommend either. Invertek Drives are somewhat new, I have no experience with them, but speak to Drives Warehouse. I would go with the Yaskawa, CIMR-VUBA0018FAA as it is more widely supported and more widely used. I also believe this is what Eisen uses in the VFD variable speed lathes/mills
All these VFDs take a bit of work to get programmed and dialed in, the manuals can be a bit daunting. The other factor is you need to know how to wire the VFD into the machine controls, I strongly do not advise connecting the VFD inputs directly to the spindle switch for the direction controls, there are just too many things that can happen on a lathe with severe consequences. It is possible to strip out the high voltage wiring to the forawrd and reverse contactors and use them to switch the forward/reverse VFD inputs. All the other controls will work the same, the motor is directly connected to the VFD. I also like to add a few other safety features. The other component is that your machine comes with a manual brake, so if used you need to switch out the current brake limit switch for a dual pole, one side is wired as before (usually a NC that goes open when the brake is applied), the other pole you use a NO contact and is wired to a VFD input that gives the freewheel command (no electronic braking when the manual foot brake is engaged). It is not a simple drop in job. You could also go with an RPC which may be less expensive and much simpler to install.
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