Spindle problems with BMC-20

[southernmenace]

I have a nineties BMC-20 that I am having a serious problem with. I gues it is only really serious since it is my first week in business for mysely, and the parts that I have promised my first customer are looking like they wont get done.

The spindle was making a knocking/rattling sound. Sounded like a nut or something bouncing around inside the motor. Got really bad when RPM were over 1000. Knucklehead that I am, I disassembled the entire motor, cleaned it out (didn't find anything either) and put it back together. Now it wont even turn on. When I turn the spindle on, it spins really slowly for about five seconds, then it faults out. "spindle fault check drive?" something similar to that.

Can anybody help me out with this. Does anyone know where I could find a good serviceman to check out this machine? It seems like everytime I try to fix anything on my equipment myself, it turns into a three week game of trial and error. I really dont have time for that right now, and would prefer to hire someone that knows what they are doing.

Please help

[JoeFin]

Well I am guessing the rotation is correct

Are we talking a "Multi-voltage" motor? Can be wired to run 208 or 480. Have you checked to make sure all the field windings in the motor are connected correctly

Stupid question I know but you have got to start some where

[southernmenace]

I have to assume that they are wired correctly. The motor was running before I took it apart, and I wired it back as it was labeled.

[trubleshtr]

The spindle was making a knocking/rattling sound. Sounded like a nut or something bouncing around inside the motor.

Please help

Sounds like the bearings are damaged in the spindle Or in the drive motor.

Did the motor shaft turn smoothly in your hand when you had it off the machine? and what about the spindle with no motor attached to it? was it smooth to turn?
Try to turn the spindle by hand with power off? Turn it very very slowly in one direction, it should be smooth, any interference/binding will veryify you need spindle re-build. (keep in mind there might be a brake on the spindle??)
If so that could also be the source of your woes.
There has to be a handful of companies that will do spindle re-builds in your area. I know in Canada where I am it is a profitable side business.

Also what was the fault code on the drive? might give you more direction to go?

[JoeFin]

Doesn't Hurco use a "Belt and Pully" on their spindle.

The belt would be my first guess as to the noise maker.

[southernmenace]

It does use a belt and pulley system. I was convinced that it was not the belt when I had disassembled it, now I am really questioning it. Both the motor and spindle spun smooth as silk when I had it apart. It spins freely even with the belt on. If the belt was the problem to begin with, I cant tell now, because I cant get the spindle to turn on. Like I said initially, it will turn very slowly for about five seconds, then it faults out.

"spindle fault-check drive system"

[JoeFin]

and of course you checked to see if your Tach on the spindle is functioning properly.

I think Hurco uses some thing like a proximity sensor which is little more then a magnet passing by a very sensitive set of contacts. If it is disconnected or not making very good contact it would explain the fault.

If it is solid state then polarity could be a problem. Either way you might want to check your service manual for instructions how to verify you are recieving the signal.

Then replace your belt

[trubleshtr]

and of course you checked to see if your Tach on the spindle is functioning properly.

I think Hurco uses some thing like a proximity sensor which is little more then a magnet passing by a very sensitive set of contacts. If it is disconnected or not making very good contact it would explain the fault.

If it is solid state then polarity could be a problem. Either way you might want to check your service manual for instructions how to verify you are recieving the signal.

Then replace your belt

Interesting, I've never worked on a Hurco, the proxy makes perfect sense if it is not picking up pulse's while you are spinning at low rpm... Is there an encoder on the motor also then?

[southernmenace]

I dont have an owners manual, and I really dont know what is what on this thing.

This proximity sensor, there is a small "fly wheel" on the top of the motor, is that it. It is a small aluminum disc, that appears to have some sort of banding around it, ( magnet maybe?) and it spins by a small circuit board. I did have to remove this flywheel in order to disassemble the motor, maybe I damaged it in some way. I have taken it back off, and checked it out, and everything looks fine. It is this area that seems to be producing the high pitched whining that I hear when I turn the spindle on.

Another thing that troubles me, is that the electric fan motor on the top of the spindle motor is not running. I believe that it is supposed to run all the time. There is voltage to it, and it is very warm. Could this fan not working prohibit the spindle motor from working?

It is a Yaskawa spindle motor. I dont know if that is any help, but I thought I'd put it out there.

Thanks for the help guys, but I am still wanting to find a "serviceman" that would be willing to take a look at this thing, so I dont cause myself anymore harm.

[JoeFin]

I'm going off a MHP-3K with updated Dynapath - 50 controller.

The manual doesn't have any servicing information for the "Spindle Speed Control Board" or the "Proximity Sensor" located on the spindle gear. It just shows 3 wires "+, -, and Sense", so that would be the little circuit board you found in the spindle.

These things have to be set relatively close to the magnet they are attempting to sense (like .100") in order to pick it up. It could be quite possible it got knocked around while you were removing the motor. Your best bet is to give Hurco a call in the morning and see if they are willing to help you out with some "Set-up Information" and perhaps some trouble shooting tips for the Tach Drive

BTW: Be sure to place an order for the "Service Manual" and "Programming Manual" while your talking to the service techs. Last thing they want is some one calling for Free information every time their machine so much as hick-ups

Good Luck

[bloke]

You took the little round aluminium encoder disc off without marking it, didn't you. It syncs the windings with the armature position. Ooops. Yaskawa time.

[Rally]

I have a user and part manual for that Machine. I think I would be able to copy that if needed. The Hurco also has a secret set of screens that is used to make base ajustments.
Let me Know!