Nature of Current consumption of BLDC motor

Thread Starter

electronicsLearner77

Joined May 26, 2012
125
If i am driving a BLDC motor using 3 phase bridge. My doubt is let us say the motor is constantly rotating at 1000 Rotations per minute, then the current drawn will be constant as long as the RPM stays at 1000? I mean to say the current will be DC current not a fluctuating current?
 

MaxHeadRoom

Joined Jul 18, 2013
20,692
The minimum current will be the energy required to maintain the rotor at the commutation rate, any mechanical load applied to the motor will increase the current to a level required to maintain the motor at the commutated rate.
Max.
 

Thread Starter

electronicsLearner77

Joined May 26, 2012
125
The minimum current will be the energy required to maintain the rotor at the commutation rate, any mechanical load applied to the motor will increase the current to a level required to maintain the motor at the commutated rate.
Max.
In case of constant RPM and constant load, i assume it should be constant current. Am i correct? Because right now all my test cases are under open load. So when i am running at fixed RPM will i get constant current.
 

MaxHeadRoom

Joined Jul 18, 2013
20,692
Essentially, yes, In the case of many BLDC motors a continuous torque rating chart is available, it usually goes from maximum at zero rpm and is fairly flat up to the rated max. RPM.
Above this is a maximum torque rating which should only be entered into for a very short period, otherwise motor damage can occur.
Max.
 
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