Ndr electric motor question

[Rutgers]

So this is my first post in I don't even know how long. Feels like forever. Quick update is I have carved one decoy in the past 10 mon this and that's the closest I've been to the duck hunting world I'm afraid. Lots going on.


I hates to be the kind of guy that pops up out of the blue needing something but for the right guy it should be an easy one so I don't feel so bad asking.

I am going to be putting together a big headstock only bowl lathe after Christmas. I am planning on using a 1:1 ratio between the motor and shaft so far as pulleys go and adjust the speed via a VFR.

Main question is does the HP and tourque get reduced along with the frequency and RPMs and if so is it reduced at the same rate?

Is there anything else I'm missing or thinking strong about that could give me trouble here?

Thanks in advance and merry Christmas happy new year etc etc

Pally

 

[Chuck J]

I'm not an electrician, but I play one on the internet...

Actually I have dozens of Variable Frequency Drives (VFD) at work, and as a user, I'll say yes, I believe you will lose power and torque, especially if you drop below 50% speed. I would actually recomend against just using a 1:1 pulley, I would size your pully ratio to get as close as reasonable to the maximum speed you want when runing at 60hz (full speed). You can actully run them a little beyond 100% speed (ie. overclock them) but I would target for the max speed to be running at 60 hz giving you the maximum adjustment within the best powerband of the motor. Also, if you didn't know this already and don't already have your motor on hand, you can get a VFD that inputs single phase electric (110 or 220 "house current") and outputs in three phase (120-208volt or 480volt) allowing you to use a less expensive motor.

I'm off to bed, give me a jingle tomorrow if you want to discuss some more...I got swamped this afternoon and (obviously) didn't call you back.

Chuck

 

[John Augustine]

I am a maintenance guy but try not to be one on the internet.
If you don't have a clean energy supply VFD's can be a headache.
What Chuck said X 2, John