# Spindle motor or controller?



## Groundhog (Aug 11, 2018)

The motor for the spindle of my Syil X4+ CNC mill quit last night. I'm not much with electronics and am not sure how to trouble shoot this. I'm a mechanic, not an electrician.

The motor will make a revolution or 2 then rattles something awful and quits. I can hit "spindle stop" and "spindle start" and it does the same thing again. I forgot to try it in the reverse direction - I'll go try that in a bit. It sounds like a bearing is out but the motor turns easy by hand without any roughness or binding.

I've attached a short video so you can hear the rattling sound.

Any knowledgeable help would be greatly appreciated.





P1040039.MOV


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## JimDawson (Aug 11, 2018)

You know two things at this point: 1) it doesn't work, and 2) the bearings seem to be OK.

It could be a bad winding, a bad Hall sensor, a loose wire, bad encoder (if equipped), or a bad controller.

I would first check the wiring for any obvious connection problems.  Tug on the connecting wires at the terminals.

Then if that's OK, then do a quick winding ohms check to ground (motor case) and winding to winding.  The winding to winding should be maybe 2 ohms or so, but more importantly should be about the same between all of them.  To ground should be infinity.

If that checks out OK, then I would take the motor and controller to the local motor shop and see what they have to say.


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## Groundhog (Aug 11, 2018)

Jim,
Thanks.
I've checked wiring and connectors everywhere but at the controller. I'll move the mill tomorrow and check there.

All fields check "OL" to ground.
blk-red  = 0.9 ohm
blk-blue = 0.9 ohm
red-blue = 1.8 ohm

Is that enough to cause problems?

I can get it to keep running (either direction) if I keep it below 800 rpm. However it makes a terrible noise (sounds like a bearing missing a few balls). With no power to the mill I can turn the motor by hand. It feels like there is a magnetic, pulsed drag bit otherwise it feels smooth.

The cover over the wire entrance (and the hall effect cover?) is cracked and shows a tiny bit of coolant or condensation along the crack. I don't see any moisture on the motor, wires or hall effect components though. One screw for the cover is a lot longer than the others and was gummed up with old coolant. As you can see from this picture someone has been in here before (buggered screw heads). There is an intact seal in the motor housing though. (I bought the mill used.)

Even though I live in a town of 45K the only motor shop only does pump motors. There might be a control electrician but I'll have to wait until Monday to start making calls.

Again, thanks for your help. If you come up with any other ideas please let me know.


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## JimDawson (Aug 11, 2018)

Groundhog said:


> All fields check "OL" to ground.
> blk-red = 0.9 ohm
> blk-blue = 0.9 ohm
> red-blue = 1.8 ohm



OL to ground is good.

The winding to winding numbers are not so good.  red-blue is 2x the other two.  The problem is that I don't know if they should all be 0.9 or 1.8.  I assume that this test was done with the motor leads not connected to the controller.

EDIT:  I just checked a new, just out of the box, 1.8 KW servo motor and the winding to winding was 1.00 ohm across the board.

The resistance you feel when turning the motor by hand seems normal.

It could be that you have a shorted winding, and the drive is current limiting and shutting down above 800 RPM. If there is an indicator of some kind on the drive, maybe you can see an error condition (blinking LED, or even a text display if equipped)


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## Groundhog (Aug 11, 2018)

No, the motor wasn't connected to anything when I did the tests.

There is no error message when it shuts down. There is one display that I neglected to look at that may show a light for an error. I'll have to re-install the motor and try it. However, even when it is running (below 800 rpm) is is no where close to right or normal.

I sent an email to the Jeff at Syil America (the dealer - just down the road from you in Coos Bay). He has always been extremely helpful with parts, but we may still have a problem figuring out what to replace. I'm sure I'll hear from him Monday. If the motor isn't too expensive I might have to just start replacing things one at a time until it runs?


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## BaronJ (Aug 14, 2018)

Hi Mike,

I've just watched your video, the noise you are hearing is the rotor hitting the stator.  I think the bottom bearing has failed !  If you use a pointed tool in the shaft center at the bottom, you might be able to move it from side to side. If so its new motor time.


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## Groundhog (Aug 16, 2018)

Nope - doesn't seem to be a bearing. I took it apart enough to be able to spin each bearing and they feel good.

It doesn't look like Syil America has a motor. My mill is 110v and the new mills have been 220v for a long time. But it doesn't seem that they are willing to try  to get one either. They gave me the email address of Syil in China and told me to try there. In all fairness I didn't buy the mill from them, but they are the only North American dealer.

But now I'm stuck without a working motor, not really sure what is wrong and not well enough versed in electronics to trouble shoot it. And it seems that I can't buy a direct replacement either (I would like to be sure that it is bad before I replace it though!).

I think I can replace the motor and controller, but I don't really know what I'm doing when it comes to the cnc's electronics. I would need some step by step instrictions. Are there any good videos or web sites to help with that?

Does anyone know of somewhere I can send it to be tested and rebuilt if needed? Or would that be cost prohibitive?

Anyone with suggestions of what I can do please chime in. I'm lost.


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## BaronJ (Aug 16, 2018)

Hello Mike,

That motor appears to be a BLDC, (Brush Less Direct Current) one.  In the picture of the bottom the shaft looks to be slightly off center.
So I'm not convinced that the bearing at the bottom is OK.  Since you have it apart are there any signs of rubbing or abrasion on the rotor or stator.


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## BaronJ (Aug 16, 2018)

Have a look at this:

https://moonsindustries.eu/downloads/BLDC-Motor-Catalog_Moons'-Industries_EU.pdf

and this.  I think this one might list your motor.
http://pjmtec.com/Products/123frame-1.5kw-brushless-dc-motor.html
http://pjmtec.com/Products/123frame-2.2kw-brushless-dc-motor.html


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## Groundhog (Aug 16, 2018)

BaronJ -
Thanks for the heads up!

I glanced at the PJM Tech web site earlier but didn't pay a lot of attention. The 123 frame you linked to is close, but not quite right.

I've learned that the "123" is the distance between the mounting holes in millimeters. I searched their site some more and found a motor with the same specs as my motor. However, part of the motor designation is different and I don't know what that means (BLM-92GM-KHB5N4 compared to my MLB-92IM-KHB5N4). All of the specs they list are the same so I don't know what the difference is - if any.

I plan on going to the local motor shop this morning. I don't think they work  on stepper brushless motors, but maybe they can give me some advise (since I am clueless). I'll take a print-out of that web page with me.


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## BaronJ (Aug 16, 2018)

Hello Mike,

The first part of the number is the motor distributors designation,  that last part corresponds to the numbers given in the PJM listing.  Knowing the physical dimensions and the motor power, you should be able to find the correct one.

I would Email PJM and give them the numbers that are on the ratings plate asking if that motor is one of theirs and if they will supply you with one.  Also ask for a price along with carriage charges.  You may be surprised !


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## Groundhog (Aug 20, 2018)

Update Monday, Aug 20th

I have a question that maybe someone can shed some light on.

I still haven't pinned down the problem with the spindle motor on my Syil X4+ CNC mill. In other words I still don't know if it is the motor, the control board or the wiring/connections. But it really doesn't seem to matter because there don't seem to be any replacement components anyway. I am going to have to replace both the motor and controller with a 220V set (the mill is now 110V).

First off, I can easily supply the 2 different voltages. But can you foresee  any problems running the spindle with 220V and the X, Y, Z axis and other components at 110V? The suppliers I've been talking too don't seem to be concerned.

Second, I've found have a system usiing a motor with the exact physical dimensions as the one I have. But theirs is less powerful and slower turning;

AC Servo Drive - H01  Frame 
0.75~1.0kW servo motor pair 
0.75kW AC servo motor  Rated 3000rpm, Rated torque:  2.9Nm, Peak torque: 7.2Nm 

while my old motor is labeled:
300V DC
4.3A
1100W
3.14Nm
3500r/min

Is that something I need to be concerned about (or is it likely my old motor label is just  a bit over rated)? My actual top speed was 3470 by hand-held tach and of course I don't know about the torque. I really was hoping for a bit more speed, not less.

(Note: Syil Corp. in China has offered to put together a similar package  -  but they haven't responded for my request for pricing and specs in almost a week. They might have a more powerful / faster set or a better price but I don't know??)

Any thoughts you have would be greatly appreciated as I am totally uncertain what I should do.

Thanks,


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## JimDawson (Aug 20, 2018)

I answered this in your PM to me, but I'll post it here also for the benefit of others.

There shouldn't be any problem running the spindle at 220 and the rest at 110. I would just bring in 220 with the neutral and split off the 110.

I can't find that motor in the DMM specs. That would be a 92mm frame, and all I see is a 86 and a 130, no 92. Is this something you inquired about directly to them?  The 0.75KW motors seem to have a 3000 RPM base speed with a 5000 RPM max speed.


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## Groundhog (Aug 21, 2018)

Jim, PM replied to  - thanks

In short; yes, I've been talking to Michael Tien at DMM. He is very helpful.

I think I will order the goodies from DMM tomorrow. He said a week or so to delivery. I'll keep this forum (and Jim) up to date!


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## BaronJ (Aug 21, 2018)

Did PJM reply to your Email ?


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## Groundhog (Aug 21, 2018)

I never did email then because it was looking likely that it isn't the motor. I just went with DMM (who Syil said would be the best route for help).

Speaking of which, I was under the imperssion that it would take several days before they could ship. I placed the order this morning and received a shipping notice to look for it Thursday!


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## BaronJ (Aug 22, 2018)

OK.  Keep the forum updated.
Thanks:


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## Groundhog (Dec 1, 2018)

Dec 2018 update:

Have been working with DMM since the end of August. Help (as promised) with installing their motor has been VERY slow between responses. Now it seems they have given up and my mill is still not working. Not able to combine the DMM drive with the existing controller.

Since it seems that controlling the new DMM motor with my existing control system will not work, I am wondering if I can replace the control system (breakout board, whatever) with a new system. I need someone or some company to help design a control system that will work with the new DMM spindle motor (or return that one and purchase something else) and any compatible existing hardware (like my power supplies, axis motors & drives, etc).

I do not want to redesign my CNC as a hobby project. I do not know or understand CNC control systems nor do I want to - I just want to get the mill working as easily as possible. I haven't found any motor or electrical companies locally who can help. I have sent all sorts of component specs, schematics and pictures to 2 on-line companies who say they can help - but they have not.

Does anyone have the knowledge to help me or know where I can go for help. I am not asking for free help. I am willing to pay but I cannot afford to spend any more without results. Between the new DMM motor/drive, wiring the shop for 220V, contactor, filters, etc. I am about $1,000 and many hours into this and no further ahead than the day it broke in August.

I appreciate any realistic ideas anyone might have


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## JimDawson (Dec 1, 2018)

Groundhog said:


> I have sent all sorts of component specs, schematics and pictures to 2 on-line companies who say they can help - but they have not.



Maybe post the same here.  We're pretty good at figuring this stuff out, and have installed a number of DMM servos.  And best of all it costs nothing.


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## Groundhog (Dec 1, 2018)

Jim, PM sent - thanks


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## BaronJ (Dec 1, 2018)

Hello Mike,

I've been watching this thread with interest !  It seems that you have been led up some dark alleys by various companies.

There is no guarantees here, but I will try to help.   Lets go back to the beginning,   Can you put the wiring back to a condition where you can run the old motor ?

If so looking at the pictures the motor has an adjustable hall sensor system.  The three screws in the slotted ring allow the hall sensor to be rotated for maximum speed or maximum power output.  Turn the speed right down so that the motor turns and carefully rotate the sensor and see what happens.   If the motor stops or tries to run backwards, turn the sensor back and then up the speed a little, and try again.

Tell me what happens.

Almost forgot !  The screw at the top of the picture should not be where it is !  It should be to the left near the other end of the slot.


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## Groundhog (Dec 1, 2018)

BaronJ,

First off - please know that I appreciate your offer of help, and may need to take you up on it at a later date. Right now I am going to try another angle.

The hall sensor has not been moved (nor have the screws) since I purchased the mill (used) in 2011. This is the first that the motor has been out or the end cap removed since I have had it.

That being said I do not really want to start trouble shooting all over again, without some reason to think a solution could be found that way.

The fact remains that there are no parts available. So, if the problem is the hall sensor, the motor, the drive, a control board, etc. it really does not matter. There are no parts. I think need to replace the entire control (but am not positive).

If you have reason to believe this can be fixed by a means other than complete controller replacement please PM me. Then I would like to set up a phone call so I can have an understanding of what you are thinking (and I am willing to pay you for your efforts). But, I need to hear a plan from start to finish, not one step every 3 or 4 days via forum posting. I don't mean to sound ungrateful, but I have been doing exactly that for 5 months and $1,000 with no results.

At the present, and with all the testing I have done (at others direction) I do not see a solution without (more) new parts.


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## BaronJ (Dec 2, 2018)

Hi Mike,

I don't think that the controller is at fault, and I was trying to determine if the failure was due to the hall devices by moving them.  It could be that one the magnets has become detached and stuck itself to one of the others inside the motor housing.


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## Groundhog (Dec 2, 2018)

Is there any way to check that other than re-installing it in the mill? I had to modify 2 ribbon cables to try the new motor and it would be a real hassle to change again. Like taking the motor apart or something?

And, if that is the case can it be repaired?

Thanks

(one reason I am looking at the controller is because of a history of brand's history of failed circuit boards.)


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## Jubil (Dec 2, 2018)

I had a similar problem with a treadmill motor. (DC permanent mag) I'm not an electrician either and don't know proper part names. But I found a field magnet loose inside housing. Motor would run but didn't run full speed and made rattling noise. I cleaned it up and degreased housing and magnet, epoxied mag back in position. It is now used on a grinder with variable speed and no problems.


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## Groundhog (Dec 2, 2018)

Sure sounds like what is going on with my motor doesn't it?

I made a feeble attempt at taking the motor apart a few months ago. I could get the ends loose enough that I could turn them and get a feel for the bearings, but could not pull it apart. I didn't try real hard because I didn't want to make anything worse. I think I will try a little harder today.

(knowing the proper names wouldn't do me any good anyway. I wouldn't know what you were talking about no matter what you call it!!)

I am also sending Jim Dawson info & pictures as he has offered to take a close look at it.


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## Groundhog (Dec 2, 2018)

I got the old motor apart. It all looks mechanically good. No dirt, obvious hot spots or alignment issues. In fact it looks almost new inside.

Does anyone know how to test it independent of the controller and/or drive?


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## hman (Dec 3, 2018)

You could use an ohm meter to do the simple, obvious checks - make sure all the windings have about the same resistance, low resistance across the contacts of the start winding switch (if any), etc.  But you've done this already (Post #3).

As for your original problem with rattling, I guess the only thing you can do is wiggle everything in sight.  You mentioned that it turned without discernible resistance when rotated by hand, but rattled under power (ie, with a magnetic field).  Try using a strong rare earth magnet to see if any parts are loose.  Are there any signs of scuffing or wear on the rotor or stator (from a loose part)?


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## Groundhog (Dec 3, 2018)

It isn't a "something is loose" rattle. It is a motor function rattle. Please run the video in the first post. Then you can hear it for yourself.


No signs of any damage or wear.


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## hman (Dec 3, 2018)

My bad.  Hadn't looked at the video.


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## BaronJ (Dec 3, 2018)

Hello Mike,

Some pictures of the internals of that motor might help.
I know that the motor has an alloy outer case but a steel inner shell, a loose magnet might not be immediately obvious as it will stick firmly to the case until a rotating magnetic field causes it to move.


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## markba633csi (Dec 3, 2018)

From the ohm readings you got back in post #3, it sure looks like one of the 3 windings is open.  The three readings really should have been very similar. Most likely one of the lead-in wire connections inside has come loose or there's a cold solder joint- might be worth a bit of investigating, you might get lucky
mark


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## warrjon (Dec 3, 2018)

It's hard to see in the video but it looks like the motor is pulsing when it spins.  Either the hall sensor has failed or there is a problem in the controller. I would check the voltage on each of the 3 phases at the controller if this is good then I would suspect the hall sensor may have failed.


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## warrjon (Dec 3, 2018)

I missed the readings in post 3. did you take these readings with the motor disconnected from the controller. If so re do the readings a reading of 1.8R is odd, but I do not think it would give you symptom you have.

From the video it seems to me that the controller is energising the wrong coils.


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## markba633csi (Dec 3, 2018)

Knowing that there are three windings all connected in a triangle, seeing a 2 to 1 difference, postulating each winding must be about 0.9 ohm and the readings he should have got across any of the three would be 1.8 ohm in parallel with 0.9 or about 0.60- there has to be one open I figure
mark


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## Groundhog (Dec 3, 2018)

warrjon said:


> I missed the readings in post 3. did you take these readings with the motor disconnected from the controller. If so re do the readings a reading of 1.8R is odd, but I do not think it would give you symptom you have.
> 
> From the video it seems to me that the controller is energising the wrong coils.


motor disconnected


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## warrjon (Dec 3, 2018)

When I said the 1.8R reading is odd I will explain a little more that I do not think it's a winding issue.

0.9R across 2 windings in series 0.45R per winding

Blu to Blk  = 0.9R so Blk is 0.45 and Blu is 0.45 all good
Red to Blk = 0.9R so Blk is 0.45 and Red is 0.45 all good

This has tested ALL the motor windings and the connections coming out of the motor

It is possible the Y connection between Red and Blu is bad. I can not see anything else that would cause the high reading it is just odd the reading is exactly double.

Gh I would locate the Y connection and open it up to check. Looks like the hall sensor bracket is adjustable, mark where it is with a pin punch so you put it back in the same location.

My first guess at the issue would be a bad hall sensor, Marantz Cd players used to have hall sensors and they went bad on a regular basis, I replaced lots.


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## markba633csi (Dec 5, 2018)

I was thinking delta, but even so, the readings should be closer I think


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## Groundhog (Dec 5, 2018)

Warrjon,
I'm thinking it is the spindle control or the main board. We cannot get the new motor/drive to work either. We are still trying to find out what exactly the output of the boards should be, but it doesn't seem we are getting the voltages that DMM expected to see.

Jim Dawson is helping me right now (off forum). So rather than trying to do too many things at one time I will continue to work with him. I appreciate your help and may ask for your expertise again in the future.

I'll keep posting any progress here.


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## warrjon (Dec 5, 2018)

OK that's a good strategy. Quite often too many cooks spoil the broth............. I will keep posting if I have any input as it may prod you guys in the right direction. I have been repairing electronics for nearly 40 years.

I will say that trying to measure voltages in a timing circuit, even with the motor running slow the DMM will not tell you if the voltage is being turned on at the correct time. You need a scope, to see the difference between the 3 phases.

A large motor like this I would expect there to be driver transistors on a heat sink - Check each of the transistors and flyback diodes in the driver circuit with the DMM on diode test (YOU WILL TO ENSURE THE MOTOR IS DISCONNECTED FOR THIS TEST). If good check all the power supply voltages on the control board, This is easy to do with the DMM. There will be a precision 5.00 (or 3.3) volts there for the logic. The 5V needs to be ±0.1v.

If the power supply is switchmode check the high frequency ripple this could be 20 - 40 kHz. You can do this with the DMM on Hz and AC volts.


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## markba633csi (Dec 5, 2018)

Agree with Warrjon, this is o-scope territory
Mark


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## Groundhog (Dec 5, 2018)

Jim suggests a scope too. Probably can't start looking to barrow one until next week. There are probably a few people with scopes around here but getting the use of one after I find it may be another thing.

But why does it matter what is wrong if there are no parts available? Wouldn't just going straight to designing a new controller that will function with the new motor & drive I already have, along with the existing axis motors & other components, make sense? Especially when those circuit boards in question are known to be troublesome?


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## warrjon (Dec 5, 2018)

Groundhog said:


> But why does it matter what is wrong if there are no parts available? Wouldn't just going straight to designing a new controller that will function with the new motor & drive I already have, along with the existing axis motors & other components, make sense? Especially when those circuit boards in question are known to be troublesome?


.

If these PCB's are know to be troublesome, I would bet that there is a common failure. I have fixed enough electronics in my time to know if equipment has a high failure rate the failures are almost always common and usually because a component/s is under rated.

Before you go borrowing a scope, look at the PCB very carefully (use a magnifier) for any tel-tail signs of scorching, this may be as minor as discolouration of the PCB or resistor can. I have seen on many occasions where a transistor looks good but on close inspection there is a small crack in the case. Or you could be lucky and there is a big hole in it.

Then test ALL the transistors, diodes and resistors on the PCB. Can you post a photo of the PCB.


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