MCP266 Accident

General discussion of the MCP motion controller product line
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rythax
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MCP266 Accident

Post by rythax » Fri Jan 24, 2020 6:01 am

Hello. Myself and a colleague were attempting to test a setup with a MCP266 that we've had running ok before but were probably not as careful as we should have been and managed to upset it (the bright flashy bang sort :( ). Connecting it to a PC showed two overcurrent warnings and a temperature1 reading of 157 which wasn't dropping so we figured that there was some damage inside.

We've opened it up and had a look inside and found that two of the FETs have had some unintentional amputations. Everything else visually looks ok.

We have some more careful colleagues who should be able to replace the FETs and then see if we've damaged anything else as well. Would you be able to provide me with the part number of the FETs so we can try to source some replacements?

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Basicmicro Support
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Re: MCP266 Accident

Post by Basicmicro Support » Fri Jan 24, 2020 9:56 am

I recommend, highly, you just send the board in to us. In all likelyhood there is other damage not visible. If we cant repair the unit(s) we will replace them at a significant discount.

Ship it/them to our contact address. Make sure you include a return address and contact information on a note inside the shipment.

rythax
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Re: MCP266 Accident

Post by rythax » Fri Jan 31, 2020 12:33 pm

I have posted this off to you from UK today. I've included a second MCP266 that failed on a different project (not sure what happened to that one but it doesn't seem to want to power up. It does have some FET damage though). I have included further information regarding both controllers on a note inside.

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Basicmicro Support
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Re: MCP266 Accident

Post by Basicmicro Support » Tue Feb 04, 2020 10:12 am

We'll take a look at them. We will need to know how they were being used when they failed, power source, voltage, load etc.. The more detail the better. If that isnt already in the note you included.

One of the primary failure modes is over voltage due to motor regen when using power supplies. The second most common failure mode is disconnecting the power source and backdriving the motors(motors become generators). This causes the same kind of overvoltage spike as the primary failure mode. The overvoltage can damage the mosfet drivers or the HV switching regulator. If it damages the driver chips you can end up with mosfet damage when you try to run it again.

rythax
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Re: MCP266 Accident

Post by rythax » Wed Feb 05, 2020 12:14 am

My tracking information says that it made it to San Bernardino yesterday so it should be with you shortly.

The motor controller that I first mentioned was being used with 2x 12V batteries and was set up to run in bridged mode powering a motor with a claimed stall current of 112A. We had installed our setup on a test rig with the motor running with no load and really only wanted to briefly see that the motor moved a little when the throttle was applied so, since we didn't have them to hand, we (foolishly) omitted the additional safety electronics (won't be doing that again). So we applied throttle, nothing really happened, then bang. Now that I'm thinking about it, that controller seemed to have a habit of forgetting settings and I had to redo them all before testing. I'm now doubting whether I re-enabled bridged mode (I'm fairly sure I forgot so that might be worth checking).

We don't know exactly how and when the second controller failed. It was being used on a rig with 2x 12V batteries that were also being charged with a power supply. This is a more permanent rig so it had the safety electronics in place. We've had a second one in place on the rig running fine for weeks. One of my colleagues thinks that it died at the same time as a torque transducer that someone incorrectly plugged a comms cable into but we don't think that would have affected the motor controller and I don't think it would have been driving the motor at the time.

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Basicmicro Support
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Re: MCP266 Accident

Post by Basicmicro Support » Wed Feb 05, 2020 10:36 am

On controller 1: That could do it. If the settings reverted somehow. There are 2 ways the unit can get reset to factory. The "Restore Defaults" menu option and by holding down the SET button while powering on. We will try to reproduce the error.

On controller 2: I'll let them know. We'll double check everything and let you know what we think caused the failure.

rythax
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Re: MCP266 Accident

Post by rythax » Thu Feb 13, 2020 1:49 am

Just checking, are you able to confirm that you have received the motor controllers?

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Basicmicro Support
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Re: MCP266 Accident

Post by Basicmicro Support » Fri Feb 14, 2020 10:13 am

Please email support@basicmicro.com. If you have tracking include that as well. Let them know when you shipped it and they will check if it has been received and let you know what the status is.

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