ENCO 3 phase to VFD questions

BigLar368

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I have recently acquired a 1980 Enco 9X42 model 2S Bridgeport clone with a 3 phase motor. I believe it to be a 2 HP motor but I really have no idea as I cant read the data plate due to it's age. I have it hooked up to a RPC now and it seems to run fine. I would like to convert it over to a VFD but being really green about this type of switch I would like some guidance before I start buying a VFD and cutting wires....lol. First question is should I just leave the RPC out of the question and just run 220V single phase to the VFD and if so does this derate the motor HP in any way? Secondly what else is needed to monitor the spindle RPM? Just in the planning stages at this time. I have the knee blown apart to clean up years of neglect. So far it looks ok. I'm not building aerospace parts. Just looking to make some car parts and other stuff as needed. Thanks in advance.
 
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Bob Korves

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Just get an adequately sized VFD and hook it up directly to the motor. The speeds you will be getting will be the same as the machine shows, times the Hertz (Hz) setting on the VFD readout, divided by 60. If the setting is 30 Hz, you will be getting half the speed, if 120 Hz you will be getting double speed. Or, you can add a non-contact tachometer to the spindle:
for really cheap and easy, or add a tachometer kit to the mill:
 

BigLar368

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Thanks for the response. What size would you recommend being I have a 2 HP 3 phase motor?
 

matthewsx

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There are plenty of threads on here about converting to a VFD. It can be as simple as just hooking a cheap Chinese unit directly to the motor and controlling from the front panel to buying a higher end unit and building a sophisticated control panel.

Options include but are not limited to custom ramp up speeds, braking resistors, variable speed controls, CNC controls, etc.

Cheers,

John
 

Cadillac

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Horsepower amperage of motor and input voltage are what you need to know to get the correct vfd. 2hp,whatever the amperage rating of the motor, and 1ph 220volts input. Just ordered a teco l510 series off ebay last week. They are nice, user friendly, good directions and not a bad price 200 bucks for a 2 hp unit 7.5amps.
 

BigLar368

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That's the unit I was looking at. I found a some Youtube videos that showed how they hooked it up but the guy in the video also mentioned something about needing a particular type 3 phase motor to use that is compatible with the VFD. I can't even read the data plate on my motor because of it's advanced age. I may just give it a try anyways. Thanks.
 

machPete99

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Newer motors will often have better rated insulation as VFD can push the motor harder in lower RPM conditions so have less cooling.
For hobby use I have not found this to be a significant issue, running 50 year old motors.
 

BigLar368

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Man....that's the kind of information I need. I think I will give the old motor a try and just purchase the VFD. One question: Does it matter if I purchase a VFD that is rated for 1 more HP than the motor I have? I think I have a 2 HP motor because from what I have read most knee mills that size came with that size motor. Would it hurt to run a VFD rated for 3 HP? Thanks for your help.
 

machPete99

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You can have a VFD thats bigger than your motor, as long as you program it with the correct HP and amperage for the motor that is connected, and it will self-limit.
 
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