Experts! My sincere apologies if this post is misplaced for this category. I didn't find any other appropriate one to post it in.

My understanding of Motors - AC or DC, Brushed or Brushless - is extremely limited. My query is related specifically to a Brushless DC Motor used in an Electric Vehicle.

As I understand, there is "self inertia" of a motor which determines the amount of minimum power to be supplied to the motor to get rotating, under a given load.

I am trying to find/compute this value/parameter, but am unable to. Is there anything in a motor's specification that can help me compute the same?

I was watching some videos to see how a BLDC motor is constructed and I could see that there's nothing else causing any friction other than the weight of the motor and/or probably the bearing of the axle. I might be completely wrong in my assumptions.

I need this to understand the minimum power requirements for the vehicle design. Hence any inputs/pointers on this would be greatly appreciated.

 

@moderator - please do move the post to an appropriate category in case this isn't the right one.

 

I think you misused a term 'self inertia' of the motor, the effort to get the motor rotating is dependent on motor continuous torque rating and the degree of load connected, most motors have maximum torque from zero rpm sloping down slightly up to the max rated rpm value.
Max.

 

Experts! My sincere apologies if this post is misplaced for this category. I didn't find any other appropriate one to post it in.

My understanding of Motors - AC or DC, Brushed or Brushless - is extremely limited. My query is related specifically to a Brushless DC Motor used in an Electric Vehicle.

As I understand, there is "self inertia" of a motor which determines the amount of minimum power to be supplied to the motor to get rotating, under a given load.

I am trying to find/compute this value/parameter, but am unable to. Is there anything in a motor's specification that can help me compute the same?

I was watching some videos to see how a BLDC motor is constructed and I could see that there's nothing else causing any friction other than the weight of the motor and/or probably the bearing of the axle. I might be completely wrong in my assumptions.

I need this to understand the minimum power requirements for the vehicle design. Hence any inputs/pointers on this would be greatly appreciated.

If there is no nameplate in the motor but you have the manufacturer's name and motor model, you can consult the catalogs published by the manufacturer online. If that is not available, you may, if that suits you, remove the rotor assembly and weigh it. Then, measure the diameters and lengths on the rotor. Knowing your initial rpm (0) and final rpm (?), you can compute for the inertia. Consult engineering forums or wiipeia on how to get the inertia.
Hope this helps.

 

Experts! My sincere apologies if this post is misplaced for this category. I didn't find any other appropriate one to post it in.

My understanding of Motors - AC or DC, Brushed or Brushless - is extremely limited. My query is related specifically to a Brushless DC Motor used in an Electric Vehicle.

As I understand, there is "self inertia" of a motor which determines the amount of minimum power to be supplied to the motor to get rotating, under a given load.

I am trying to find/compute this value/parameter, but am unable to. Is there anything in a motor's specification that can help me compute the same?

I was watching some videos to see how a BLDC motor is constructed and I could see that there's nothing else causing any friction other than the weight of the motor and/or probably the bearing of the axle. I might be completely wrong in my assumptions.

I need this to understand the minimum power requirements for the vehicle design. Hence any inputs/pointers on this would be greatly appreciated.

Hello,

Inertia does not stop a body at rest from moving (rotating) it only limits the acceleration. For an interesting extreme example, you could have 1x10^8 units of rotational inertia and only 1x10^-8 units of force and eventually the body would rotate up to an infinite speed. It would get there pretty darn slowly, but eventually it will get to a very super high speed as long as there is a true zero friction.
The fact that time comes into the picture means that either you are talking about friction, or you are talking about inertia and acceleration that combine to make a rotation to a certain speed possible in a certain amount of time.

So you may have to clarify a bit.

Also, the load will have inertia and could also have some added friction.

 

I think the OP has left the building,
about 5 months ago.
Max.