Search found 926 matches

by rew
28 Mar 2016, 21:02
Forum: General
Topic: Is it possible to use the vesc for wheelchair hub motor
Replies: 9
Views: 2081

Re: Is it possible to use the vesc for wheelchair hub motor

Haha! So I guessed correctly that there were more decimal points missing. :-)
by rew
28 Mar 2016, 20:51
Forum: General
Topic: case for VESC
Replies: 10
Views: 3288

Re: case for VESC

12S is about 50V. 3kW, 50V is 60A. The current determines the heat-losses in the FETs. IRFS7530 at 1.15mOhm gives 4W per motor phase, or about 12W total. That will be in the FETs. Oh! there are also 1mOhm shunts. Two of them. So add another 7.2W from the shunts. The FETs also incur switching losses....
by rew
28 Mar 2016, 20:34
Forum: General
Topic: where does the mosfet temp value come from?
Replies: 6
Views: 2404

Re: where does the mosfet temp value come from?

I have been looking at the code.

The code is prepared for more sensors. One for the PCB (CPU? DRV8302?), one for each mosfet, and one for the motor.

However, in current implementations many map to the same physical sensor. This means that adding the sensors later on is easier I guess.
by rew
28 Mar 2016, 20:04
Forum: For sale, orders, etc.
Topic: VESC-based board(s) for sale....
Replies: 42
Views: 11011

Re: VESC-based board(s) for sale....

As you told that you are using eagle. How much layer are you using for each individual PCB? Edit.: Maybe this paper http://irf.com/technical-info/whitepaper/directfet.pdf is interesting for you. I will take a look at the whitepaper. I try to stick to two layers. PCB manufacture is easier and cheape...
by rew
28 Mar 2016, 09:05
Forum: FOC
Topic: Question about ADC Injected channelks configuration
Replies: 5
Views: 2071

Re: Question about ADC Injected channelks configuration

I THINK the second sampling is deactivated with DEFINEs. Doublecheck for yourself. That code is only executed once at startup. So removing code is going to make the startup of your ESC about half a microsecond faster. Why bother? I don't really know the answer to your second question. I suspect: If ...
by rew
28 Mar 2016, 08:59
Forum: For sale, orders, etc.
Topic: VESC-based board(s) for sale....
Replies: 42
Views: 11011

Re: VESC-based board(s) for sale....

The IRF7749 shows as "no longer stocked" here at Farnell (EU). i.e. they think there are better products available. I searched for "directfet" and got a load of results. When I selected >=60V, there was just one that wasn't "no longer stocked". I want to be able to get ...
by rew
27 Mar 2016, 20:03
Forum: General
Topic: Is it possible to use the vesc for wheelchair hub motor
Replies: 9
Views: 2081

Re: Is it possible to use the vesc for wheelchair hub motor

The "nominal voltage" and "nominal power" allow us to calculate the maximum current: 100A. That's too much for the current VESC.

P.S. If there are more decimal points missing I may need to revise my conclusion.
by rew
27 Mar 2016, 20:02
Forum: General
Topic: case for VESC
Replies: 10
Views: 3288

Re: case for VESC

It helps to know what voltage and current you are expecting. But even at the maximums, I would think that thermally connecting the fets to the case will be better than nothing.
by rew
27 Mar 2016, 18:06
Forum: For sale, orders, etc.
Topic: VESC-based board(s) for sale....
Replies: 42
Views: 11011

Re: VESC-based board(s) for sale....

RE PM/email vs posting here: Agreed. But if for some reason you prefer PM or Email I'm game too. No not altium. Eagle. Why not DRV8302? Well, I calculated the 12V current for VESC and found we were already close to or over the allowed current for the DRV8302. I asked TI what could be done about abou...
by rew
27 Mar 2016, 16:56
Forum: General
Topic: VESC at high Voltage (and KV)
Replies: 14
Views: 4421

Re: VESC at high Voltage (and KV)

So my 50A max motor should be rated at "max 1.25V". Yep, if you wanted to make a brushless gimbal out of it (which is always stalled so all the consumed power is turned into heat) the max would be truly 1.25V (at 50A) to not overheat it without external cooling. In that situation 250rmp w...

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