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View Full Version : Help for MOTOR 2.2 Kw and control board.



BILLYBOUM
31-12-2013, 12:56 AM
Hi Everyone !

I'm coming to you in the hope you would help me with some questions :

I have BF46 milling machine ( from OPTIMUM ) which is not CNC but that have a big brushless motor driven by a control board.

Brushless and board : that's why i try to post here hopefully.

FACTS :

On a hard work, at low speed, with a large tool, the machine stopped suddenly .
I looked at the board and found 2 blown fuses ( close to power 220v entry point )
I changed them and they blew again almost instantaneously.
Hand turning free the nose of the milling is not as usual : there seems to be a slightly hard point during hand rotation.
Looks like the motor has passed away...

-1- if the load on these type on motor overpasses the torque capacity, there is no other protection than fusing the engine together with the fuses ( and may be the board as well :mask:)?

-2- the controller board is not able to stop the work and let the engine cool down ?

-3- there were a little bit of oil into the motor : is that bad for the motor ( does it crunch the varnish on copper wires ? or dissolves the glue fixing the magnets ? :strawberry:) - oil was left in gear box -located below motor- during machine transportation to another workshop and milling was tilted down to horizontal for the trip.

-4- the motor ( fit vertically ) has 2 end caps, top one with some circuitry : i could not separate the rotor neither the top, only the bottom cap came apart from end shaft bearing : is there anything of some interest to visually check out the rotor ? ( should it be a smooth solid uniform part or are there some magnets that can be split out from that bit ? )

-5- do you think, in case the motor ( rotor ? ) is damaged, that the board could be damage as well ?

-6- i changed the board not so far ago, and it cost me 1000e.... is there a mean to repare those board rather than changing as a whole at customer cost ? ( i'm not a businessman, i'm working by my own... ) That is to say : manufacturer is not very helpful except at heavy cost.:whistle:

Sorry for my mistakes in English language, and many thanks for reading and helping if you have any idea !:beguiled:

Web Goblin
31-12-2013, 07:10 PM
Looks like the motor is inverter driven.
1- Some inverters will shut down depending on what type of fault they see on the motor windings and some don't, they just blow up.
2- As above
3- Any oil should not have been able to pass between the gearbox and the motor as there should be oil seals on the shaft connecting them so I wouldn't think that would be the problem.
4- You would need to separate the motor from the gearbox first before stripping down the motor. Testing it electrically would be the first step. Disconnect it from the inverter and check each winding to ground. They should all show a high resistance between the windings and ground, in the megaohms range. Then test each winding to the other two. They should show equal resistance for each winding between each other and depending on the motor this could be quite low, ie a few ohms.
5- If the motor has gone down it could quite easily take the inverter with it if it does not have any overload or short circuit protection.
6- These inverters are normally repairable particularly if it is a standard pcb type. Most decent electronics repair shops should be able to do this.
If this is the second time this has gone down I would get the motor checked out to ensure it is ok and seriously think about upgrading the inverter to give you some protection from the motor faults.

Meant to add that most manufacturers will quite happily sell you another board as its good for their sales figures and dont do repair work.

EddyCurrent
31-12-2013, 10:00 PM
Agree with Web Goblin,
3. A small amount of oil would not be of much concern, but obviously better without it, it's the oil seal that is suspect. It may also be that it's the gearbox at fault, maybe it lost oil during transportation and that oil has not been topped up.
4. It sounds like the circuitry on top might have something to do with speed or position feedback.
Web Goblin is talking the stator, the rotor you mentioned is the rotating part in the middle and in an ac induction motor would be extremely robust, look like a solid lump of metal with laminations, and unlikely to be a problem, though joints on the end of the cage have been known to fail.

BILLYBOUM
01-01-2014, 12:04 AM
Thank you guys for your comments and brain storming's.
I got the motor out again and clamp it into a vise.
Eventually took some pics.
Oil seems to come from weak seals letting thru during horizontal transport.
I found one tiny wire i had to sold again on the Hall sensor on top of motor ( inside top cap )
All wires are rigid and insulating plastic of bad quality.
Observing the main control board, there are no hot points or burned points or inflated condensators, any other ideas for what to look for ?

Another question : i can't figure out what is the metallic box under the main control board ? is it a rectifier ? it is sealed ( by soldering stuff ) and written in Chinese on top of it.
I would be happy to find out that the problem is there.... who knows ?
11123111251112611127111281112911130111311113211133 11134111351113611137111411114411142

irving2008
01-01-2014, 12:38 AM
The metallic box in the last pic with the chinese writing is an EMI filter to stop interference & noise from the VFD getting back on the mains supply.

Web Goblin
01-01-2014, 12:48 AM
I was busy looking at the pictures when irving replied. The box is as he says a mains filter. If this was faulty it would cause the fuse in the supply plug to blow and not the ones on the control pcb.
You could remove the heatsink clamps from the six power transistors at the rear of the board and check to see if any of them look cracked or burnt. If the motor windings check out ok with your test meter you would need an insulation tester to further check for any insulation faults to other windings or ground.
Have you tried powering up the control pcb without the motor attached to see if it blows the fuses?

BILLYBOUM
01-01-2014, 02:12 AM
Didn't know about EMI filter !

Thank you both : you are clever ! :thumsup:

I will remove the heatsink clamps this afternoon to see if any cracks/burnt appears.

Motor checks out OK ( as far as i know ... )

ALL THE BEST AND A HAPPY NEW YEAR GUYS !!!!!!


:joker:

PEACE

EddyCurrent
01-01-2014, 07:58 AM
Happy New Year !

See the circuit board mounted on the end of the motor, make sure it goes back in exatly the same position. You can see it has slots to allow rotation.
If you are using a 500v Megger type insulation tester keep it well away from the same circuit board, only test at the windings (U, V, W), if it's just a multimeter that will not be a problem.

On the main board there is a white connector with 2 white wires going to it, beside it is a 3 leg component mounted on a small vertical heatsink, well the legs on that do not look good, it looks in fact like someone has changed it before. Maybe this is a component that blows often ?

There is a rectifier with GBU 12G written on it, this could also be causing the problem.
http://www.datasheets.pl/bridge_rectifiers/GBU12A.pdf

http://www.youtube.com/watch?v=dqkT6hF0O3E

BILLYBOUM
01-01-2014, 02:38 PM
Hi Eddy, many thanks for your helping documents and comments, and i'm impressed by your sharp eyes and knowledge !!!

-1- Yes i ticked marks to position-back the rotary circuit on top of the motor, but yes i try to test everything on this circuit - including small Hall-effect tripods - is that deadly for them ( my multimeter is a FLUCKE, switched to BuzzerOhm-meter ) ?:apologetic:

-2- I suppose i have to de-solder the GBU12G to test it correct ?

-3- you are right as well for the 3 legs that look re-soldered : do i have to de-solder this component as well and how come is possible to test it ?

-4- i have the "old" contol-board where i plugged by mistake ( at the wrong place ) the rpm information : may be it is easier to check and repair this board ? ( the present board is burning the 2 protective fuses almost instantaneously, the previous one just doesn't work and leaves the fuses OK by the way )

Thanks Eddy for your time and ideas !:tongue:

EddyCurrent
01-01-2014, 03:23 PM
Hi Eddy, many thanks for your helping documents and comments, and i'm impressed by your sharp eyes and knowledge !!!

-1- Yes i ticked marks to position-back the rotary circuit on top of the motor, but yes i try to test everything on this circuit - including small Hall-effect tripods - is that deadly for them ( my multimeter is a FLUCKE, switched to BuzzerOhm-meter ) ?:apologetic:

Using the Fluke meter is okay.


-2- I suppose i have to de-solder the GBU12G to test it correct ?

Yes


-3- you are right as well for the 3 legs that look re-soldered : do i have to de-solder this component as well and how come is possible to test it ?

ideally, can you see a number on this component ?


-4- i have the "old" contol-board where i plugged by mistake ( at the wrong place ) the rpm information : may be it is easier to check and repair this board ? ( the present board is burning the 2 protective fuses almost instantaneously, the previous one just doesn't work and leaves the fuses OK by the way )

You can use this to make a comparison with the other board, you can test the components without de-soldering them for a start then if you find a difference you can de-solder it to test it properly.

BILLYBOUM
02-01-2014, 12:49 AM
Hi,
This afternoon i managed to :
-1- desolder the GBU12G ( was very complicated because of 4 legs to heat together and some kind of rivets clamps fitted on the 4 concerned holes of the board ... long story )
-2- test the L7824 fitted with a tiny heatsink : the resistance was a lot different along one leg from top to bottom : i decided to replace this component with the same one from my second board.
-3- put everything back together.

Tomorrow : put the board and the motor back onto the mill and test with new fuses....we will see !
Some pics :
11148111491115011151111521115311154111551115811159 1116011161

irving2008
02-01-2014, 01:01 AM
The L7824 is a 24volt voltage regulator. Resistance measurements across it's legs tells you nothing about it's condition.

They're pretty indestructible, having built-in thermal shutdown, output current limiting and short circuit protection. About the only way to kill one is to exceed the max input voltage, apply a reverse input voltage (e.g. if the rectifier has failed short-circuit) or connect the output to a high voltage. If it's been replaced or needs replacing then there is likely to have been something catastrophic happen to the board and many other parts may also need replacing.

BILLYBOUM
02-01-2014, 01:12 AM
Thanks Irving : about L7824, i thought some people bent this component too much and broke the middle leg ( ground as far as i understand ) and repaired it with a tiny bit of metal included in solder ( that was looking really clumsy )
Anyway, i replaced it with the one from my second board because it looked just better ( can't hurt though )

As a conclusion, because the GBU12G was tested ok, i'm afraid nothing has changed and fuses will blow again.
W'll see !)):whistle:

Many thanks anyway !!!:cheerful:

EddyCurrent
02-01-2014, 08:57 PM
Any luck with this yet ?

BILLYBOUM
03-01-2014, 12:23 AM
Thanks Eddy :adoration:

No much luck but not desperate because i tried this sequence :

-1- powered up the board without connecting the motor : everything looks OK ( many leds light up, speed control screen light up )

-2- plugged in the motor : nothing special happened !!! ( power lines plus Hall control pack )

-3- started the motor w/o any load : BING ! everything goes dark in my workshop...:hororr:

-4- unplugged the motor and try to power again : the board looks still alive !!!:love-struck:

Difference before and now :

-1- i changed my usual power line ( 220V fuse protected 20A ) to another line ( differential switch 10A protection )

-2- the 2 fuses on the board ( T10A ) don't fuse anymore - before, fuses were 6.3A ( no tempo ) ( but the differential switch now trips on my main power board )

Question :

Do you think hall sensors can "dislike" too much load requested on the motor - even for a short while ??? ( because that moment was the origin of the problem : i requested too much an effort on the milling so that it blocked suddenly the head rotation and stopped and blow the fuses )


Many Thanks Guys !!!

irving2008
03-01-2014, 07:10 AM
Sorry to have to say this, but your lack of understanding of electronics means you are clutching at straws. Almost certainly one or more of your output MOSFETs is faulty. Simple resistance measurements may not reveal which as it may only fail under stress. Your only option is to replace them all with known good NEW ones, you cannot assume the ones in the other board are good. Even then there may be some other failed component which will cause one or more of the new MOSFETs to fail, e.g. a dodgy high-side driver, leaving you back at square 1. You need more knowledge and more equipment than a multimeter to fault find this board.

Question: the GND wire on the hall sensor pack that you had to resolder. Was that disconnected after the fault or did it become disconnected when you disassembled the motor?

EddyCurrent
03-01-2014, 09:27 AM
It's true what Irving is saying but in the interests of keeping things cheap and easy try this first.
I'm guessing you mean the RCD is tripping, in that case you may have put something to ground that should not be, it only takes a few mA to trip it. Check the motor to make sure nothing is down to earth on it.

Web Goblin
03-01-2014, 01:01 PM
I didn't realise that you have stalled the motor while cutting. As Irvine says you have probably taken out the output stage. Try replacing all of them as he says and see what happens. But you could also have cooked the motor as well which a simple test meter wont show. You need and insulation tester to check it out correctly.

BILLYBOUM
03-01-2014, 01:25 PM
Hi Irvine,

The idea was to keep things cheap and practical considering the price of that board is around 1.000 euro - so even if i could replace all components, it should be cheaper than buying a new one at manufacturer.

From the start, I came to a specialist in electronics and TV boards : he said he was not able to repair my board ( despite all his oscilloscopes and stuff in his workshop ... ) so apparently, this kind of problem is not so easy to solve even for professionals.

I understand and thank you for your technical comment :


Your only option is to replace them all with known good NEW ones, you cannot assume the ones in the other board are good. Even then there may be some other failed component which will cause one or more of the new MOSFETs to fail, e.g. a dodgy high-side driver, leaving you back at square 1. You need more knowledge and more equipment than a multimeter to fault find this board.

I will try to see if i can find second hand board plus motor from people transforming this kind of mill into a hi-speed CNC, and in the meantime, i'll continue to investigate what is wrong on my board.

irving2008
03-01-2014, 01:45 PM
A hi-fi/TV repair place wouldn't know where to start. This is a specialist job - you need to know how brushless controllers work to start with. I suspect the manufacturer wouldn't bother fault finding, its too labour intensive, they'd just replace the board. If it was mine, I'd have a go, but then I've designed these controllers before so I have some idea what I'm looking at.

EddyCurrent
03-01-2014, 02:15 PM
Thinking about what next, maybe going off the rails ? (but that's how I like to think about stuff :abnormal:)
Looking at the parts list, does it have to be a motor of that type ? I know it would be great if it just fit right on but would a standard AC motor + inverter (working in sensorless vector speed mode) adapt ? I was thinking the shaft from the original motor could serve as the adapter, it's a lot less cash.
http://www.optimachines.com/attachment.php?id_attachment=345

BILLYBOUM
03-01-2014, 02:40 PM
Eddy : Going the same way ! : i was looking since 2 days into another solution for this mill, replacing the motor for 380V plus inverter, or even replace the whole machine for a conventional mill ( 380 plus inverter ... either )

Anyway, i'll have to sell it and better to repair it before... so coming back to first point !

May be some people converting these kind of mill to high speed CNC will be interested....

Thank you again eddy ! :beer:

hacklordsniper
25-11-2014, 04:13 PM
Im so sorry im rising such old topic from the ashes, but it is the only one on the internet with same problem as mine. I recieved my machine and it could only go to about 500 RPMS less than specified. I was sent by manufaturer adjustment procedure and while trying it the motor has jumped 5800 RPM and fuses exploded. My PCB is a newer variant with IKCS22F60F2C . It could be seen PCB was hand repaired before as many other junk Chinese packed on this machine (i was an one time buyer, so great way to get rid of various defective parts that were not shipped to Optimum). I replaced the burnt PFC stage, IKCS22F60F2C, input rectifier and my board works now. However the motor does not work and PCB only makes short 6 flashes (error code maybe?) and freezes. I managed to get a new tested board, but this behave same as one i repaired.

Im suspecting the motor, but never worked with BLDC motors in past. How should i test this motor? Its same as motor allready shown here. Should i open it up and test Hall sensors?

BILLYBOUM
25-11-2014, 05:06 PM
Hi everyone,
Thanks for those who help me : the mill is working now with a new 380V 3PH motor and an inverter 220V 1PH -> 380V 3PH.
I designed a new support to hold the motor, plugged new coupling device in the mill, and all is ok by now. Sofar so good.
Special thanks to Eddy ! :beer::beer::beer::beer::beer:
Post might be closed.

EddyCurrent
25-11-2014, 07:49 PM
How should i test this motor? Its same as motor allready shown here. Should i open it up and test Hall sensors?

There will probably be 3 main terminals, you should check the resistance between each one and they should all read the same.

hacklordsniper
25-11-2014, 08:42 PM
2 months of trouble, but started working tonight. So i removed the motor, powered the hall board with a bench power supply and tested the output of them, all of them worked ok. I measued ressitance to ground and between terminals, it was ok. I tried insulation tester and all windings seemed to be ok. I tried applying DC to terminals and all of them slightly moved the motor.

I reinstalled the motor again and same thing happened. While starting the motor ON/OFF switch gave 6 flashes and went silent. As i was speaking some rude words to it i pressed the on button few times in series and motor started. Now it works ok. I tried for research purpose to disconnect motor terminals and it again gave 6 flashes and go out. After pressing on button 3 times in row, the PCB "resets" and it works nicely afterwards.

I guess the PCB goes to somekind of protection mode after the motor has been disconnected, and 3 pushes of the ON button reset it. Even the manufacturer does not know this (or does not want to tell).

Im attaching a picture for this PCB as future reference if someone will google this situation in future. Furthermore i will give discovered procedure for adjusting speed range. Pressing the lower button on small PCB you adjust the maximal speed with speed pot, and pressing the upper button you adjust the minimall allowed speed.

BILLYBOUM
26-11-2014, 09:45 AM
:disgust:Holly sh.t !!! i discarded the whole crazy system because of lack of information about this reset procedure…. thanks to "manufacturer" who doesn't KNOW or even worse doesn't TELL ( it is not written in the documentation provided ) and who probably "prefers" to sell control boards ( +1000e ex vat ) AND motors ( +1000e ex vat ):disgust:
So PM for spare parts to bargain ( 1 motors plus 2 boards ):joker:

hacklordsniper
26-11-2014, 12:09 PM
:disgust:Holly sh.t !!! i discarded the whole crazy system because of lack of information about this reset procedure…. thanks to "manufacturer" who doesn't KNOW or even worse doesn't TELL ( it is not written in the documentation provided ) and who probably "prefers" to sell control boards ( +1000e ex vat ) AND motors ( +1000e ex vat ):disgust:
So PM for spare parts to bargain ( 1 motors plus 2 boards ):joker:


Do you have the pneumatic changer on your Optimum mill? If so i would be interested to buy your boards

BILLYBOUM
26-11-2014, 12:15 PM
Sorry, i havn't this option

hacklordsniper
26-11-2014, 03:35 PM
Sorry, i havn't this option

Thank you, i guess the board is not very compatible with my machine. It can also be seen there is much changes on my version of board.

Does not matter, i would anyway buy this boards for study and repair. I would not buy motor tough, so if you want to sell me this PCB-s, please write to my PM