losses in permanent magnet DC Brush motors

[bernardg]

Hello,
I am a design Engineer at MPOC, and we manufacture "permanent magnet DC Brush motors".
I am trying to come out with an equation to calculate the total heat that is being generated due to the various losses like 1)Winding losses 2)Iron losses 3)Friction losses 4)Brush losses 5)Short-cut circuit losses.

I was wondering if anyone of you done any research in this field... or could give me some suggestions, as to which book I should read to learn more.

Every one, thank you in advance for being generous with your time and expertise.

Regards,
Bernie.

 

[MarcoHenry]

I don't know if this can help:
1)Winding losses, are the main losses: Irms^2 * Ra ( Irms = FF*Average current, FF (Form factor) for pure DC= 1, for six-pulse converter= 1.06 and for Single phase converter= 1.35, all of this Rule-thumb used at Reliance Electric)
4)Brush losses, rule of thumb is 1 Volt drop per brush, watts will be Iave * 2
Hope this can help

 

[jbartos]

Suggestion: Visit

http://www.compumotor.com/catalog/cataloga/A13-A16.pdf

http://www.globe-motors.com/dc_motor.pdf

http://mechatronics.me.vt.edu/book/Section3/motormodelling.html

etc. for more info

 

[AT1000]

hello
I work as a servo engineer in a motor and drive repair shop.
though most are ac servos the d.c. motors that come in for rewind or overhaul using ferrite magnets must all be re-magnetised on special wound formers we have made otherwise the speed and torque are all over the place.why not put true permanent magnets in mfg. or is this too costly. once over the name plate current watch out for de-mag.as for formula i'm just hands on carbon.
at1000

 

[IRstuff]

There really is no such thing as a "permanent" magnet in the sense that you are talking about. All such magnets can get demagnetized through heating and external magnetic fields. The best and strongest magnets are all built to mechanical shape and then "formed" with external magnetic fields. The strength of the magnet dictates the amount of external field required to set the "permanent" characteristics.

Your typical kitchen magnet stays permanent because it experiences no stresses, while those in PM motors experience eddy fields and heat that weaken the magnetism.

TTFN