Motor Torque vs kV
#1

Is it true that motors with lower kV have more torque then motors with higher kV? Usually higher amp draw produces more torque and higher kV motors tend to draw more amperage. So I would think a higher kV motor would also have more torque as well as RPM. The main down side being heat produced.
This would not take gearing into consideration as that would obviously change torque and RPM ratios. More of a motor shaft hooked up to a dyno scenario.
Can anyone clear this up? Thanks
This would not take gearing into consideration as that would obviously change torque and RPM ratios. More of a motor shaft hooked up to a dyno scenario.
Can anyone clear this up? Thanks
#2

There is a motor parameter called Kt that describes the relationship between torque and current. It is inversely proportional to Kv; as Kv goes up, Kt goes down.
If you put two motors on a dyno that had different Kv values and measured the current on each phase, you would indeed see that the motor with the higher Kv value requires more winding current to produce the same torque.
If you put two motors on a dyno that had different Kv values and measured the current on each phase, you would indeed see that the motor with the higher Kv value requires more winding current to produce the same torque.
#3

Does this relationship apply the same way to both Brushless and Brushed motors?
#4

Yes it does - this is something common to any motor with permanent magnets.