Loss of heat from a motor

[d3adwalk]

Sorry I'm a newbie and french then my english is not so good.

I need to calculate the loss of heat from a motor in proportion of the energy given to the motor.

It's not very well explained then if you need more information I'll tried to give it to you but i'm a new employee then I want to impress him. I know there is different motors but I prefered to have the more information possible because he didnt expect that I'll necesserely understand what I'll bring him..

Sorry to bother you with my lousy questions!

Maxime.

 

[CH5OH]

heat loss=electric power consumed-shaft power delivered

EPC=sqrt(3) x voltage x current x cos(phi)

SPD=(2x(pi) x angular Speed in rpm * Torque at shaft/ 60

cos phi,speed and torque needs to be obtained since they all vary more or less in fuction of load (SPD)

 

[imok2]

For a 3 -20 HP at 85% efficiency standard motor figure about 400 BTU/HP
Go Here:

http://www.engineeringtoolbox.com/electrical-motor-heat-loss-d_898.html

 

[hollandhvac]

Also see ASHREA fundamentals F30.4 table 3A there you have a tabulation of motor sizes, motor types and situations
a when motor and driven equipment is in the airflow
b when motor is out of the airflow but driven equipment is in the airflow.
c Motor in the airflow, but driven equipment is out of the airflow.