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Re: efficiency of the ev3 H-bridges ?

Posted: 09 Nov 2013, 16:24
by philoo
so you mean overall 3A for all and everything?
3A is the internal current limit of driver chip. but its continuous rating is 1.5A (2A peak) per motor. But it can only provide current provided by upstream fuse, battery, etc...
It looks to me like there are two separate thermal fuses one for each of the two motor driver chips (Outputs AB and CD). Not sure what current they trigger at though....
I really need to open an EV3! Have you made any photo of the main board?

Re: efficiency of the ev3 H-bridges ?

Posted: 09 Nov 2013, 16:29
by HaWe
I would never dare to open the case.
But I'm sure Xander has already done it - there's nothing between heaven and earth that holds him back :roll:

Re: efficiency of the ev3 H-bridges ?

Posted: 09 Nov 2013, 16:39
by gloomyandy
Not opened the EV3 up, but the Lego schematic seems to show 2 fuses for the two drivers.... But the scan quality is very poor so can't read the part numbers and other details...

Re: efficiency of the ev3 H-bridges ?

Posted: 09 Nov 2013, 16:44
by philoo
OK, we have the same ;)

Re: efficiency of the ev3 H-bridges ?

Posted: 09 Nov 2013, 17:01
by philoo
I opened an EV3... I didn't want to take the risk of breaking something, so I didn't go too far away, but enough to see the fuses. Indeed, there are 3 of them, all rated 1.1A. So maximum available current is 1.1A (permanent, something around 2A for a short time) for 2 motor ports.

Re: efficiency of the ev3 H-bridges ?

Posted: 10 Nov 2013, 15:23
by HaWe
edit:
srry, I must have misunderstood:

you wrote THREE fuses at 1.1 A each, but we have 4 motor ports.

So there are 2x single fuses for 2x single motors each
and 1 fuse for 2 motors altogether?

Which motorss by which fuses? e.g.:
A / B / C+D ?

Re: efficiency of the ev3 H-bridges ?

Posted: 10 Nov 2013, 16:21
by gloomyandy
Hi Doc,
There is one fuse for motors A/B one fuse for motors C/D and one fuse for everything else (sensors etc.)

Re: efficiency of the ev3 H-bridges ?

Posted: 10 Nov 2013, 17:24
by HaWe
ah ok, now I understand. Thank you Andy!