motors their applications and limitations PMDC vs BLDC

[Electro nS]

hi guys

i want to know for low voltage 24-72v what is the deciding factor between DC motor ? Brush or brushless

1- limitations in power can PMDC go as high as BLDC ex:10Kw or 20Kw ??
2- efficiency ?
3- magnets rare earth , or ferrite has to do anything ??
4- size to power ratio ?
5- cost to power ratio ?
6- availability ? future proof ?
7- difference in servo applications ?

plz discuss your valuable opinion :lol::lol::lol::lol::lol:
and if this post should be moved to another section please advise ! i posted here because i assume the engineers working in motors and controllers are usually power electronics experts

cheers

 

[chuckey]

7. For servo application, accurate position of rotar required, PMDC is used AKA "stepper motor". because of the difficulty of manufacturing very large magnets, I doubt if these are available for a greater power then a couple of kilowatts. BLDC is normally 3 phase so the rotar can only lock at 6 positions , so the shaft position is only know to be +- 60 degrees.

1. Big magnets are difficult to make, so no.
2. Brush are better as commutation losses lower.
3. Ferrite would only be used for specialized motors with a very high commutation speed.
4. Brushed motors smaller - no driver module needed.
5. Brushed are cheaper.
6.To future proof, buy only motors with a specified frame size ( NEMA)
Frank

 

[Electro nS]

7. For servo application, accurate position of rotar required, PMDC is used AKA "stepper motor". because of the difficulty of manufacturing very large magnets, I doubt if these are available for a greater power then a couple of kilowatts. BLDC is normally 3 phase so the rotar can only lock at 6 positions , so the shaft position is only know to be +- 60 degrees.

1. Big magnets are difficult to make, so no.
2. Brush are better as commutation losses lower.
3. Ferrite would only be used for specialized motors with a very high commutation speed.
4. Brushed motors smaller - no driver module needed.
5. Brushed are cheaper.
6.To future proof, buy only motors with a specified frame size ( NEMA)
Frank

7- PMDC is not AKA stepper motors !! stepper motor are closer to bldc , and when u add enocder you can know the postion of the rotor anytime in both types

1- as i know even BLDC has magnets right ? so why is this a limitaion for brushed
3- as i know ferrite is the main stream and neoyduim is the specail version or is there another type ?