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Old 03-12-2017, 11:26 PM   #11
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Call it a night, hit the turps and sling in a warranty claim, it's clearly rooted!


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Old 03-13-2017, 03:46 AM   #12
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Motor has got no play and turns over smooth except ripply sort of feel like a stepper motor, but that's it for me ,they can fix it.
John


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Old 03-18-2017, 02:38 PM   #13
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Call it a night, hit the turps and sling in a warranty claim, it's clearly rooted!

I agree, mess with it too much and the OP will end up getting blamed.

Greg
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Old 03-18-2017, 07:21 PM   #14
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Motor has got no play and turns over smooth except ripply sort of feel like a stepper motor, but that's it for me ,they can fix it.
John
That "ripply" feel is indicative of some sort of problem - sounds like a permanent magnet (PM) motor with an armature winding short - could be as little as a single loop - but it plays havoc with the VFD. The motor fails to vector smoothly and sounds can vary from the delicate tinkling of tumbling broken glass to a cement mixer filled with scrap iron.

If it is a PM motor then you can test drive it with a cordless screwdriver (effectively driving the PM motor as an alternator) and measure the three output phase voltages (disconnected from the VFD for this test) one phase will be low - there's your problem.

You might also have a phase short.

P.S. edit - if the "ripply" feeling goes away when disconnected from the VFD - then the problem is in the VFD.

If it's a squirrel cage rotor then none of the above apply and I'm baffled.

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Ken
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Old 04-12-2017, 06:41 AM   #15
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Hi John,
How did you get on? Did you have any joy from the supplier?
Regards,
Alan
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Old 04-12-2017, 06:27 PM   #16
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From what i can see it is a brushless motor so maybe the problem is in the switching transistors of the motor driver , it could be just a bad solder joint causing one of the dc phases to work intermittently or not switch polarity fast enough to keep up with the other phases .
Its a bit like having a brushed motor running and then slamming it in reverse then back into forward at high frequency .
Either way it is covered by warranty so the seller should fix it and if you are not familiar with mains voltages or circuit boards that work at those voltages i wouldn't go poking around one as there are usually some capacitors that could be still charged to mains potential and can stay charged for a long time after the machine has been unplugged from the power socket .
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Old 04-13-2017, 12:38 AM   #17
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Yes that is my thought as well that one of the phases is dropping out .
It's apparently a servo motor.
Anyway parts are suppose to be on the way.
Cheers
John
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Old 04-13-2017, 04:30 AM   #18
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Default Problem with the new lathe

If they haven't asked for the faulty board back set it up next to the new one and check the solder joints on both boards , if any look dry or incomplete it may be worth re soldering them before fitting the new board and then keep the old board for a spare and if you spot something that looks like a dodgy solder joint on this board give it some attention with a soldering iron .
Just watch out for those charged electrolytic capacitors - they will bite ya !
If you can , please take some photos of both boards so we can take a look at them and others who follow can compare with their boards etc .
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Old 04-13-2017, 06:56 PM   #19
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Good idea to compare two circuit boards as often I have found engineering changes implemented with an additional component or two soldered on top. It's then easy to upgrade the failed board and have two working again.

Worst case, if there are discrete components save the old board for donor parts. The machine needs to run for a lifetime or two and shouldn't be abandoned in the future because of failed electronics which is usually what happens.

Another easy test is to look for swollen capacitors. This seems to be a common failure point these days and easy to fix.

Since re-soldeirng every wire connection and replacing the speed control pot, my mini-mill has been reliable. I don't worry about it anymore and the project to re-power with a treadmill motor is on the shelf.
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Old 04-14-2017, 12:57 AM   #20
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Thanks guy's.
If they allow me to keep the the dud board I'll take it into work for the sparky's to have a look at. I'm a robotic and automatic guided vehicle operator so the fellows at work may have an idea.
Cheers
john


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