Enco Mill - motor takes a few tries to get to full speed

[tcweb]

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 have managed to trip the breaker once.

I turn it off, wait a few seconds, try again. Usually after 3-4 tries it fires up and goes to full speed. The motor is a 2HP, currently wired for 110v, since I don't have a 220v option in my garage. The motor is a dual capacitor model.

I'm wondering if it could be something like a bad run capacitor? I'm not a motor expert by any means. The contacts on the switch look OK, and all connections are tight, as far as I can tell. Since it does fire up and run smoothly after a few tries, that should mean that the coils are OK, right?

Any advice is appreciated. If you are a fellow RF30/Enco owner, and have a source for a motor or motor parts, let me know. The current motor appears to be chinese. I believe it's the original motor that came with the mill.

-Tom

 

[CluelessNewB]

I don't have an RF30 but I have worked on many motors. My guess is starter cap. They are cheap and not hard to replace.

 

[tcweb]

Thanks. Motors that have dual-caps...would both need to be replaced? Since the motor fires up right away (to partial speed), before it stalls, would that indicate that the starter cap is OK, but the run cap may be faulty? I"m not an expert on how motors with a run cap (dual capacitors) actually work.

 

[CluelessNewB]

I would replace both caps while you have it apart. If it's more than 10 years old I would probably change bearings also although that has nothing to do with your problem, that's a bit more work than the caps.

 

[warrjon]

I had a 2hp single phase motor on a 12x36 lathe and it used to eat start caps ($80 each here). There is a centrifugal switch in the motor that disconnects the start cap, if this is faulty and / or sticking intermittently it WILL take out the start cap before you can turn the motor off.

Remove the start cap (cut one wire) and turn the motor on, does it start (albeit slower) and run. If it does the run cap is good and your issue is the start cap. I removed the start cap and ran the motor without it, just takes the motor a little longer to come up to speed, as long as the motor is not starting under load like in a compressor.

 

[tcweb]

Thank you both. I just pulled the covers off, and took pictures of the caps, so I can try to find replacements.
Someone had labelled them "start" and "run" with a sharpie. the "run" cap looks like one side is a bit flattened, not sure what that's about.

 

[kvt]

I have not looked under my cover, I have a RF30 2hp wired for 110. Has one hump cover on it.
I can take it off and look if needed. but is sounds like you may have a diff motor on yours.

 

[tcweb]

is your motor Chinese? I believe my Enco was made in Taiwan back in the 80's. (but I'm not 100% sure). Here are some pictures of the capacitors. Do I need to match them exactly, or can there be some variance from these specs?

The first pic is the run cap. Second is the start cap.

 

[markba633csi]

On the voltage rating: match or higher, never less. On the capacitance value, try to get close to the original value. More is a bit better than less. For example, for the 35 uF one, 40 would be better than 30.
mark

 

[tcweb]

Thanks. Does the "CD60" and "CBB60" represent the size of the cap? Or do I just have to do my best to find one that fits inside the covers, adding a spacer as needed?