Hello,
I'm trying to power a ME0708 DC Brushed motor, with VESC 6. No matter what setting I change I can't get it to pull more than 20 amps. When I do a direct motor to battery connection it draws 40 amps. Is the 20 amps a built in safety limitation in the code for the hardware? If so, what is the DC motor current rating on the new VESC 75/300 controller?
Thank you
Hi Cory
it would help to know what settings (mainly amperage of battery+motor) you have in your VESC installed? How have you connected the DC? Between two (of the three) phase cables, right?
Cheers
Sam
Pedelec usage in combination with a GoldenMotor MagicPie3 BLDC
Have you setup the motor and battery current limits? I don't think many people use VESC for DC motors, so its relatively untested.
Motor: http://www.motenergy.com/me0708.html
Controller: vesc 6 w/ no regen
Battery: 14s13p Samsung 25R cells
Connectors: Anderson SB50
Battery & motor set @ 50 amps
Using just two phases A & C
That's not being very kind to the VESC. The DRV chip will burn at 60V, you're running it from a battery pack that will be 58.8V fully charged. Oh and I'm pretty sure that motor will happily draw >>50A so the SW current limiting may not catch it in time and fry the VESC. This is a good use for the VESC 75/300.
Yes I did read that and im only charging to 54 volts and regen has been disabled. I cant draw more than 20 amps right now, 40 would be nice. I don't want to buy a vesc 75/300 unless someone can tell me if it wil do more than 20 amps / whats the limit? if the vesc 6 is limited to 20 amps in dc mode by design that's fine, I would just like to have conformation from someone. Thank you everyone for your help :)
Hi Cori
I would (have no layout currently available) to change the used phases to R + T (Phase 1+3) as afaik the two shunts are there (A+C) detecting the current flow. Maybe your Motor is else not really detected what it draw and therefore the FETs limited?!
Every phase can take/deliver surely up to 100A each when fully on, so if you have not set anything limiting (50A is a good value) your Brushed motor should be at full throttle. Using the wrong phase would explain the misinterpretation. As mentioned before: the VESC is a DC polyphase controller, and as every BLDC controller it could control one, two and even three Brushed motors at once, but there are better solutions (no offense intended Ben), because a simple switch controller (I build such with two half bridges or one FET array + relays for reverse) in the 1980's with big success for my then brushed RC Mono boat who consumed 50V and 150A (and more....) which was not available (=payable) as it is now. As long as you have a high switching frequency (>10kHz) you get a good low to high reaction with a minimum of special parts. The VESC is far beyond such a simple Switch controller (for DC motors) and again not optimized for such a duty.
Cheers
Sam
Edited because I get a hold on the V4.10 schematics see attached pic.
Pedelec usage in combination with a GoldenMotor MagicPie3 BLDC
Thank you Sam
I went out and tried every possible combination of phases and only A&C and C&A (reversed direction) worked. still limited to @20 amps, Frank or Ben is the VESC 6 coded to a limit of 20A for DC motor mode? If so what is the limit on the new VESC 75/300? Would like to know before I buy.
Hello Cory
that limitation applies of course only to the two shunt VESC V4.x, not to the (not so widely used) V6.x. I'm not aware of a limitation by either version for brushed motors, but it's not intentionally build for it either.
Cheer
Sam
Pedelec usage in combination with a GoldenMotor MagicPie3 BLDC
It should work with more current, but I haven't tested DC motors too much. There was a bug in the current measurement for DC motor though, which could have made some difference. It is fixed on github and will be included in the next VESC Tool.
I'm planning to make much better support for DC motors with the new gpdrive module later, but there is still some work needed. I also don't have too many DC motors to test with. The gpdrive runs current control in the same was as FOC does, and hance prefers having the motor resistance and inductance to get good control parameters. It is not so easy to measure the resistance on a dc motor though, as they spin up as soon as any current is applied.
Well im always happy to help with testing, I'll try and get the github ver. installed and try that then. I'm assuming the new "gpdrive" is in the vesc 75/300? So I'll also purchase a 75/300 then also. Thank you for taking time to respond to my question.
Didn't realize that there was a VESC 6+ now, so I picked that up and VESC 75/300. BTW will the new VESC software update be released tentatively some time here in the next month?
Thanks
WOW !!! Didn't expect them to show up today. Thank you for A+ service.
"There was a bug in the current measurement for DC motor though, which could have made some difference. It is fixed on github and will be included in the next VESC Tool."
So I saw ver.1.0 was out, so I updated and was able to pull 50 amps now thanks to the update. So yes, thank you for finding and fixing that bug.
Now that I have had some time to do some testing, it seems I can't go past 50 amps on either VESC 6 or VESC 75/300 using Ver 1.05 software.