Ok so try to put 1000 v through a motor and see if the current doesn’t increase and fry the motor. Of course more current will flow through a conductor the if voltage is increased, that is basic knowledge. U=RI
And you didn’t understand the difference between electric effect and mechanical effect. You are saying 3000 w of mechanical work is more than 1.4 Nm at 1000 rpm, yes that is what i said as well. But if the efficiency of the example motor is only about 5% like at very low Rpms, drawing 3000w of electric power will only get you 150w of mechanical work.
Look at the typical bldc characteristics below. At 500 rpm you will only get 10% efficiency. So feeding the motor 3000w of electricity the motor will produce 300w of mechanical power and 2700w of heat.
If you did the same thing at but at 4600 rpm where you have 95% efficiency you would get 2850w of mechanical power and 150w of heat.
I’m afraid 1000v would flash over before you could get an amp read. Just make sure your wearing HV gloves and a blast shield. Amps still stay the same by the way. A conductor carries the same amps regardless of volts. Like those copper windie things in an electric motor. Seriously kids don’t play with high voltage
Are you trolling?
“Ohm’s law states that the current through a conductor between two points is directly proportional to the voltage across the two points.”
I could be wrong here @snorren, but I think what is happening here is you are talking about what it says in a text book and @MoeStooge is talking about what happens in practice.
knowledge v’s wisdom
By the way if you do decide to put 1000v through a small bldc motor, get that shit on video dude
Well if the textbook would be different from reality I probably would have been fired years ago from my job as an mechatronics engineer. But I appreciate the peace gesture Cobber
Yup a #6 copper conductor is rated to carry 115a regardless if the voltage is 50 or 5000. If you knock the amps up to say 200 the wire will heat and burn regardless of voltage. Ft lb is a mechanical measurement and a motor that makes 3000w makes more than 1 ft lb of torque weather it is a 10v or 100v motor.
Its interesting to see that the conversation came down to the very basics: Ohm’s law.
Both @snorren and @MoeStooge have a point. Ohm’s law has to hold, obviously, so V=IR, and for a given resistance, if voltage is increased, current will definitely increase.
But, @MoeStooge said that according to the formula Power=VI, as voltage is increased, current should decrease…hold on…FOR A GIVEN POWER!
See, a motor has power (torque and speed) characteristics FOR A GIVEN VOLTAGE, for example, at 24V, as you give the motor more current, the power increases. But if you talk about changing the voltage, the motor no longer has the same characteristics, and has a different power curve. So now, with increased voltage, will come increased current, at an increased power, and if a motor is not rated for that, it will overheat and burn. That’s why motors have a rated voltage. At that given voltage, as you increase the current, the power increases.
I think we should also look here about controller limits. Basically if u take 12s controller which can do 50A, then with higher voltage more watts produced. So in this case higher voltage better (unless u take lower quality vesc which might dye sooner because of 12s)
Also better for the wires and other parts, as less heating should happen.
I think motor power most of the time should be concluded from both amps and voltage, in our case I think maximum suggested would be around 12s anyways but then practical tests should be made to figure it out precisely.
Here’s a real world application. The motors I run are rated 60v at 200a. 12kw.
I run at 30v. 200a 6kw.
If I tried to get 12kw at 30v at 400a the motor would quickly fail.
As long as you stay under your Volt and amp ratings your motor came with you will be fine.
Higher voltage won’t increase torque. The current in the motor won’t be lower. Kt won’t change w voltage
There isn’t really a voltage limit of a motor other than the enamel magnet wire and the bearing speed ability.
The esc bucks down the voltage so the pack may be 50v but the esc is sending much less through pwm and creating an effective voltage. When going faster the motor produces its own voltage as a generator, the back voltage, and the esc will increase it’s output related to that so you would only maybe have the full 50v applied to the motors at top top speed where the back voltage is so high and needs be overcome. In that instance you’re subtracting the back voltage it’s fighting against and you’ll end up with still maybe only a couple of volts across the motor winding
The kv/kt of the motor and the amps put to it and the wheel diameter or gear ratio decide torque solely. Kv and kt encompasses a lot as it reveals torque produced per amp period
