Heat load calculation

[ribbert]

We have a 600V 3 phase 500 KVA motor generator set. I need to do a calc to determine how much this unit loads the A/C system for this building. I have all the electrical data for the motor and sychronous generator. Where can I find guidance on how to do this calc?

 

[electricpete]

You can if you have any two of the three values Out, In, Efficiency. If the machine is running you can certainly measure the electrical power input and output precisely with the right equipment.

Out = Motor Generator Output Power
In = Motor Generator Input Power
Losses = Power Dissipation to be removed by ac

If you have output and input power:
Losses = In - Out

If you have In and Eff
Eff = Out/In = (In-Losses)/In
In * Eff = In - Losses
Losses = In*(1 - Eff)

If you have Out and Eff
Eff = Out/In = Out/(Out+Losses)
Eff*Out+Eff*Losses = Out
Losses = Out * (1/Eff-1)