There are three components. Motor. Esc. Battery. U set the current limit from the battery to esc. You set the limit from esc to motor. The current going to the esc can be much less than comes from esc to motor.
There is a formula and based on the speed ur at…the lower it is the more the voltage is converted to amps.
“Transformer”- Ren. Read above.
http://vedder.se/forums/viewtopic.php?t=207
No, the 50A may flow continuously, even with 5A battery current, (PWM increases the current and reduces the voltage seen by the motor)
So the battery only sees 5A on average… the motor will see 50A continuous
Motor Amps Limit can be higher than Battery Amps Limit because PWM modulates Volts.
From Vedder
The current draw from the battery will only be high on high duty cycles, so when going slowly you can have high torque and high motor current without drawing much from the battery since the motor inductance, input capacitors and PWM work like a switched mode power converter. For this to be safe you need and ESC with current control and/or current limiting. If the ESC does not measure and care about the current, you can get very high battery and motor currents when giving full throttle on low speed with hub motors and high battery voltage.
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No sinusoidal ?
The link brams put one above says specifically that it’s continuous 5amp from battery
I don’t think any of those are variables. Simply stated if ur running at lower speed…volts gets converted to amps for the motor by the vesc you’ve been driving me nuts telling me I’m wrong and don’t know what I’m talking about for two weeks (we’re neighbors) and constantly giving me water analogies or something !!! And now ur saying there’s other variables. No variables.
The flow of liquids in a pipe is analogous to flow of current in wires. Voltage is analogous to pressure and current to the volume of liquid flowing. Resistance can be thought of in terms of diameter of pipe.
If two containers are pressurized to same pressure and a pipe is connected between them, you wouldn’t see any flow because the difference in pressure is =0. If tank A is at higher pressure than tank B then liquids flow from A to B and it is proportional to the pressure difference(voltage difference). Also if it proportional to diameter of pipe(or the resistance of wire). There are ways to think about conductance and inductance in similar ways, but it’s a tiny bit more complex.
So to answer your question @Hummie , the voltage difference between two points decide how much current flows though the wire(no conductance, no inductance, only resistance). The two voltage which are fighting each other are the battery voltage(fixed) and the back emf(proportional to rpm). As long as the battery voltage is higher than back emf, the difference in voltage is still there and hence current passes through the wires, that current produces magnetic field which in turn produces the torque in the motor. When the motor is spinning so fast that the back emf = battery voltage, the difference is zero and hence no current can be pushed though the coils anymore and hence no torque is produced. That is called the theoretical no load RPM. True no load rpm is less than theoretical no load rpm because of friction losses.
What the VESC does now is control the battery voltage going to the motors. From zero to max battery voltage. You might ask what happens when the controlled battery voltage is less than the back emf, well braking happens.
@ brams No sinusoidal?
No, not in standard bldc mode. This is what I have been saying all along. You have to think two separate circuits, the only link is Watts (not voltage and not amps, only Watts)
One side is battery and esc input. It’s DC voltage of the battery and the amps are whatever is needed (if not constraint by anything).
The other side is esc output and motor. It’s AC voltage. And the voltage is based on rpm and Kv of the MOTOR (plus something for loss).
IT IS INDEPENDENT OF THE BATTERY VOLTAGE!
Yes!!
So voltage at the motor is only dependent on rpm and Kv! And current is drawn from the esc. How much? As much as needed to have enough Watts to propel the rider.
NOT THE SAME AS BATTERY CURRENT, NORMALLY MORE.
And of course the rider has to open the throttle enough to convert (commutate) enough V and A from the battery side to the motor side.
Wattage is the link! Both sides have the same Watts (neglecting losses). They have different A and V.
A Volt is a Volt An Amp is an Amp Now and Forever
The Vesc doesn’t convert volts into amps. What it does is control the flow of current (amps) While keeping the voltage constant.
A transformer?
I’ve said my piece. I’ve quoted vedder and Ren who make these things. I can’t explain how it happens but was told its analogous to a transformer. If u go to vedders site and search for answers you’ll find me asking this question already and getting the answers from the source
Wattage is definately kept the same and no free lunch. All I’m saying is the amperage and voltsge that the motor receives is in a different circuit and can be vastly different. As far as over time an average …I don’t know and makes sense but for what I’ve read on vedders site it might be operating very different. They say as much