I know that mechanical efficiency is n= power output/power input, but I don't know how to find each of those. I have to find the efficiency at full load running speed.
I was only given mechanical losses (1.04kW), and that's why I'm confused because most equations talk about copper and stator losses and I'm not given them.
If anyone could help explain what equations to use that would be a great help!
Here's an update of other values I was given:
Input voltage= 400V
No. of phases= 3
Running speed= 11.9(rev/s)
Total number of poles= 24
Rotor R per phase= 0.66(Ohms)
Rotor X per phase= 5.3(Ohms)
Effective rotor-stator turns ratio= 0.86:1
Mechanical losses= 1.04(kW)
% of running load at start-up= 83%
I don't know if you needed all of that but was not sure what you need to work out efficiency.
Here's an update of what I know so far:
Efficiency (n)= Pout/Pin
Efficiency= (Protor - Presistive rotor - Pmech losses)/(Protor - Presistive rotor)
And to find Protor (which is power flow in rotor)= P= VI. I got my current by doing Ir=s(N2/N1)E1/sqrt(r2^2+(sX2)^2) as it wasn't given.
To find Presistive rotor would I do Prr= ((3Protor)*(2I))-r.
So Effiecincy= ((Protor - Presistive rotor - Pmech losses)/(Protor - Presistive rotor))*100
Are these equations right?