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The "low ESR" is a secondary property of the capacitor. There WAS an issue with a capacitor being "marginal" on it's primary property: capacitance. When that happens, you simply need the bigger (in capacitance) capacitor!
- 06 Jan 2018, 18:13
- Forum: Hardware Problems
- Topic: DRV fault code on FOC detection
- Replies: 9
- Views: 1253
That pulldown resistor is connected like that due to layout issues. Where it is connected now is connected to the "normal" place through one or two 0.001 ohm resistors. So the resistor still does its work, but at 0.002 ohms more resistance. With the DRV, you can DISABLE the FET outputs. In...
- As you don't use the built in current sense from the DRV8302, do you think it is a mistake to deal with regular mosfet driver ? Yes, my variant of the VESC uses just normal LM5109 or IR2xxx FET drivers. The VESC started out with "guidelines" from TI which said: you need only two current...
You do NOT want to tell both motors to do the same speed. Any minor error will cause the motors to fight each other. With PWM control, you get a slightly better situation. The effective resistance of the motors will allow them to adjust a bit to small errors. Still it is quite possible that one moto...
Looks nice, but read my posting from 15 months ago: You are not effectively cooling the mosfets. any heat generated inside the mosfet has to travel through the 10x higher thermal resistance to the outside of the FET.
I asked TI about providing the PVDD externally. They answered! The response: DO NOT DO THAT! That might be (and probably is) just CYA policy, but that's the official word.... (I use a DCDC converter in an application. The datasheet says: "min load: 10% of max load". In my application the l...
- 02 Dec 2017, 20:30
- Forum: VESC Projects
- Topic: VESC in homemade lathe/drill press
- Replies: 11
- Views: 574
Yes. The torque constant is actually the same as the motor constant Kv. Or depending on the units the inverse (*). 245Kv is 245 RPM / Volt = 245 (RPM/V) / 60(sec/min) * 2*pi (rad/rotation) = 25 rad/sec/V That means the torque constant is 1 over that, or 0.04 Nm/a. So for 40A you get: torque = 0.04 N...
I have had my lab powersupply backfed from braking the motor. Once with the powersupply at its max and a few times less agressive with some margin on the powersupply. But yes, the VESC will remain powered even if it cannot drive the fets as long as the motor turns....
- 02 Dec 2017, 19:26
- Forum: General
- Topic: 180 degree commutation with sensors vs standard 120
- Replies: 13
- Views: 765
No, From what I read above, the "180 deg commutation" is simply BLDC but with an extra motor coil powered up. (Y or Delta does not matter). But if we think about what we want to achieve.... We have a permanent magnet in an electromagnetic field. We want to set up that magnetic field that h...