Spindle Motor Problems

[NylonAdmiral]

After resolving my communication problem, I started running the first program to test out the mill.

Everything seemed to be going fine until the power tripped out.

This was caused by something else but unfortunately cut the machining job short.

I since fired the mill back up again to see if I could get the job going but now seem to have a new problem.

I started the program running and when the G code reached the command to set the spindle speed, the spindle started up but seemed to be struggling to pick up any speed. The spindle speed seemed to be quite "jittery" and couldn't get up above a low RPM.

I stopped the program, homed everything, then went to issue a manual spindle start (whilst on the jog tab) to see if that would work.

The spindle wouldn't move at all.

I then tried repeating the program and the spindle no longer moved, no matter what I do it doesn't seem to move at all anymore. Everything else work and each axis operates normally.

Unfortunately I don't know where to begin with trying to diagnose and rectify the problem so any suggestions would be greatly appreciated!

Thanks

[NylonAdmiral]

I checked all the fuses I could find and they all seemed to be OK.

I fired the mill back up today and the spindle ran this time although only slowly and jittery again.

This time however it ran for a short period of time and then I found smoke coming from what I assume was the spindle motor!

I'm guessing this means the spindle motor may well need replacing.

Does anyone know if a) this is likely or whether it's indicative of something else or b)what a suitable motor would be to replace it with?

Many thanks.

[angel-tech]

if there are brushes on the top of the motor give them a clean and check the depth

[NylonAdmiral]

Thanks angel-tech, it doesn't look very easy to get to but I'll have a look at it this evening. It might take me a while to post my findings as it might take a while to get it out.

[NylonAdmiral]

After finally managing to remove the motor, I pulled the brushes out to inspect them.

To be honest, I'm not really sure what a good brush or a worn one should look like.

Does anyone have any idea whether or not these brushes look any good or not?

Thanks

brush.JPG (101.91 KiB) Viewed 42298 times

[angel-tech]

they don't look too bad, were they sticky to get out or did they slide out easily?

[Martin]

They look like new. I presume the spindle is free to turn by hand?

I don't think I have elver come across a faulty motor before on a Starmil. Are you able to check the output from the spindle drive? You should have around 120 volts DC when asked to run at top speed.

[NylonAdmiral]

Thanks both. Although I don't have a lot of experience to go on, I thought they looked OK too.

They certainly came out pretty easily and yes, the spindle turns by hand. I replaced the bearings in it earlier in the year so I know they're good too.

So far I haven't tried to check any outputs as I'm not sure where I would need to try and read the 120 volts from?

I'm not sure if it's of any help but I previously mentioned about the smoke coming out of the top of the mill from what looked like the the spindle motor. The smoke had quite a distinctive smell too.

After removing the brushes from the motor, the holes they were removed from still smelled like the distinctive smell from the smoke. Even though the brushes may be OK, I can't help but wonder if this smoke was indicative of something wrong with the motor.

If anyone can advise where I might check the output on the spindle drive then I can have a closer look at this this evening.

Thanks again.

[Martin]

It does sound like the spindle motor has gone from what you are reporting.

The bad news is it's a sod to remove & refit in my experience. You should be able to send it off to a motor repair company to have it checked/repaired.

In order to remove it you will need to remove the motor coupling to drop it through the plate it fastens to.

[NylonAdmiral]

Thanks Martin. I already took it out. It was an absolute nightmare to do and I'm not looking forward to putting it back together...

I found this company that is listed as a Baldor small DC motor repair centre so will give them a go.

https://www.ansteeware.co.uk/2009/Electr ... pairs.html

Failing that, I believe replacement motors are available from the States but they're $484 USD!

Whilst I do that, I think it's still worth checking the 120v output if anyone can knows where I would measure this?

Thanks

[Martin]

You should have a Sprint DC drive fitted.

viewtopic.php?f=15&t=2275&hilit=sprint

You will need to measure the armature voltage between A+ & A- on the drive. Don't forget it's DC. The motor is a 180 volts.

[NylonAdmiral]

Hi Martin,

Thanks for that link. It looks like the one I have so I'll try and inspect it more closely this evening.

I just spoke to the chaps at Anstee & Ware who service and repair these motors. I'm sending it in to them next week so will post the results of their findings.

Thanks for your assistance so far.

[NylonAdmiral]

Hello again,

I was so busy over Christmas that although I ultimately managed to remove the motor from the mill, I never managed to remove the wiring and get it sent off.

Anyway, I'm back to it now and want to get it sent off.

One question though, the attached picture shows the wiring into the connector block on the back of the machine.

Does anyone know if it's possible to remove the wires from the connector block or will I simply have to cut them?

Many thanks

Wires.jpg (70.7 KiB) Viewed 42190 times

[Martin]

You need a pin extractor to remove from the barring plug.

[NylonAdmiral]

Thanks Martin

I don't suppose you happen to know of a suitable tool do you?

I've just looked online and they seem to come in a range of sizes and types.

[andy_con]

viewtopic.php?f=47&t=3891

I had issues on my triac with the motor, kept tripping my rcd. Once I gave it a mega clean I've not had any issues since.

But I had smoke coming from the top of the motor

[NylonAdmiral]

Hi Andy, thanks for your comment.

I've actually now sent the motor away to have it looked at. Hopefully they'll be able to test it properly for me without it costing too much to sort out!

[NylonAdmiral]

I just thought I'd update this thread in case anyone else experiences the same problem.

After having the motor professionally assessed at Anstee & Ware, they discovered that the armature was completely burned out and believe it is most likely attributable to a "magnetism fault". I can say that although this was not the answer I was hoping for, they were very helpful.

Unfortunately the damage is bad enough that it's more cost effective to buy a new motor than get the original reconditioned.

I'll updated again once I've got the (expensive!) new motor installed and the mill running again.

[angel-tech]

you may want to consider a chinese three phase motor if you can get one to fit in the starmill and gear the motor down with a change of pulleys.

[NylonAdmiral]

Thanks Angel-Tech, but rather than trying to find something and make it work I elected just to buy the correct motor.

I got it delivered a while ago but only just got round to finding the time to fit it.

The wires on the old motor were:

Pin3 - Brown
Pin4 - Black
Pin5 - Green/Yellow

CutWires.jpg (252.32 KiB) Viewed 41670 times

The wires on the new motor are:

Brown
Blue
Green/Yellow

MotorWires.jpg (232.57 KiB) Viewed 41670 times

Am I right in thinking that the new wires should go:

Pin3 - Brown?
Pin4 - Blue?
Pin5 - Green/Yellow?

Thanks!

Feel like I'm getting pretty close to having the whole thing back together now!