I think my Rong Fu mill's original motor is about to die?

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stioc

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During the milling the motor came to a stop (with the click/relay noise) and started buzzing (like electricity energizing a transformer) as if there's load on it but there was none. I flipped the switch to off and then back on (even tried reverse) and it just made the same buzzing noise. Pressed the reset button on the motor, same thing. Pressed it a few times again and flipped the switch to on and it started working again. Then same exact senario 20 mins later. So a couple of questions:

1. Is it the brushes? the run capacitor? or something else. I don't know much about motors...but sounds like I'm about to learn lol

2. If the motor is toast I would love to convert it to a VFD because changing two belts at the top is such a pain I mostly don't and run at incorrect RPMs. What style motor will bolt up to this guy?

1570306750560.png
 
Actually, upon closer look using the infrared temp gauge it seems the motor's just getting too hot. Makes sense because I mounted a boring head and had it running at low RPM for a long time.

However, still interested in guidance on getting a bolt-on motor to convert to VFD.
 
Sounds like a capacitor failure, I would replace both the run and start. capacitor first. Frequent switching single phase motors on and off can result in over heating of the start capacitor and the motor will not turn and just sit there and buzz.
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Enco Mill - motor takes a few tries to get to full speed

Hello experts, I have my Enco mill (RF30) up and running and have an annoying problem. When I turn the switch (forward or reverse, doesn't matter), the motor immediately kicks on and comes up to about 1/3 speed, then stalls or "pulses" at about that speed. It must pull a ton of current, as I...
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You would need to see the motor frame and shaft size (diameter and length), as well as the mount to the machine. My read from other posts is it is a metric motor, if so I would look at the Leeson Metric motor specs and see what compares to the dimensions of your motor. The site below list these motors with specs and drawings. Ideally if you plan to use the mill as a single speed with a VFD you may want to opt. for a larger Hp motor in particular for low speed work. Below the motor's base speed of 60Hz the Hp drops off in a linear fashion. Alternative is to over speed the motor to say 120Hz and belt it down, but usable power range is still probably in the 30-120Hz range in particular with heavier loads. There is no down side to running a 1750 RPM motor to 2X its base speed in this application,

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Lots of information already posted on converting the RF30 to VFD, just an example of an old post. These days the Teco L510 seems to be a popular VFD for use on mills. If you plan on having the VFD controlled by the CNC/use the mill in this application then I would invest in a better motor (inverter/vector) and a better VFD like the Hitachi WJ200, Teco E510 or similar VFD. You have provided us with very little information as to the mill, setup and type of work/needs.
 
Thanks for the info and the links Mark. I pointed a fan at the bottom of the motor and it has been fine so far.

I'll research the VFD/motor option more and see what I find out. I don't intend to control the motor through CNC. In fact, for quick projects lately I've just been running the machine manually using the arrow keys etc :)

@Superburban, how long did it take to replace the caps do you recall? a couple of hours or an entire day/weekend?
 
stioc said:
@Superburban, how long did it take to replace the caps do you recall? a couple of hours or an entire day/weekend?
Click to expand...
Probably 1/2 max. While I did it, a went ahead and replaced all the seals in the head unit. The whole thing was the better part of a day. I have the HF version of the RF 40, with the geared head. so it was like 3 or 4 seals.
 
Cool, thanks. Not quite sure where the seals go and the part# etc. but I'll look around.
 
stioc said:
Cool, thanks. Not quite sure where the seals go and the part# etc. but I'll look around.
Click to expand...
If I remember, yours has belt drive so no seals. Mine has gears, an oil box, and shift levers, and seals to keep the oil in.
 
Yes, mine's a dual belt system...aka. the pain in the neck system that needs to go away :D
 
I’d change the capacitors first.... AND THEN check your voltage at the motor when running to make sure you aren’t suffering from a voltage drop issue. Wouldn’t be the first time low voltage was overtaxing the motor.
I find it’s always best practices to wire dual voltage machinery motors to run at 230 volts. Running them at 110v is almost a recipe for early failure IMO.
 
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