Inductive generators, what is their output compared to their horsepower rating

[swdepew]

Let say I have a 3 phase ac motor rated at 40 hp. Now I'd like to be able to convert this to act as a single phase induction generator (I hear is possible but I don't know much about it). driven by an ICE at around 1800 rpm. What would its power output be in kilowatts. Or more importantly how would I find that out? What other information from the motor do I need? I appreciate your time in looking into my question. Thanks.

 

[russ_watters]

Welcome to PF! All you really need to know is the efficiency. A good 3 phase motor/generator can be 95% efficient. After that, it's just knowing the English-metric conversion factor for hp to kW...

 

[swdepew]

Thanks for that Russ. I wasn't sure if it was as simple and converting HP to kW. A few more follow up questions. If we assume an induction generator is 80% efficient is that referring to mechanical input to electrical output? Meaning the electrical output will be 80% of the mechanical input? If so does that mean I will need an ICE that will produce 20% more power than the rated output or would I just produce 20% less electrical power? Also how do I find out how much torque is needed from the ICE?