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ev3 large motors: do they have a built-in fuse?

Posted: 26 Oct 2013, 08:36
by HaWe
About ev3 large motors: do they have a built-in fuse?

I obeserved the following issue (reproducable):

A metal tank tread chassis was driven by 4 large ev3 motors on the lawn.
For experimental reasons they all have been connected directly to a 12V battery (4500mAh).

Now under very heavy load weight the motors have been braked until standstill, but after removing the load completely they did not immediately restart rotating but not until about a minute later, after then everything worked fine until the next braking. Voltage was > 11-12V at any time.

This made me think of maybe kind of bimetal fuse inside the motors.

Re: ev3 large motors: do they have a built-in fuse?

Posted: 26 Oct 2013, 09:10
by mightor
I just ripped a motor apart and see something that looks a lot like a thermal fuse.

Image

Note that is not the final production hardware, so the final hardware may look slightly different.

Regards,
Xander

Re: ev3 large motors: do they have a built-in fuse?

Posted: 26 Oct 2013, 09:15
by HaWe
ahaa... thx!
8-)

Re: ev3 large motors: do they have a built-in fuse?

Posted: 28 Oct 2013, 13:17
by philoo
Looks a lot like a 0.75A rated Bourns MF-MSMF075 resettable fuse... (the same used in all PF battery packs)

Re: ev3 large motors: do they have a built-in fuse?

Posted: 28 Oct 2013, 15:06
by HaWe
thanks for confirming my suspicion !