 # Single phase motor power?

Hello to all. I have a question.How can I calculate a single phase motor active power? tnx.

Actually I have a motor like below.But I don’t know how to calculate active output power?

The one you show is rated at 1.5 shaft metric horsepower (1.5PS on nameplate) I belive a metric horse is 0.986 imperial horse (746watts) so the imperial output is around 1.48HP

If the motor you have is not identical to the photograph then without further information we cannot answer the question.

What is supply voltage What is load current What is power factor What is efficiency What is ........

What is the relationship between output power and V,I,cos pi in Single phase motor? tnx.

If the motor has a PF of 1 and 100% efficient then output power is the product of V and I in watts
If cos phi (not pi) is less than 1 (which it always will be in an inductive device) then output power is V x I x CosPhi x Efficiency.

Efficiency is rarely specified on a nameplate but using the motor you illustrated we get

PS = V x I x Cosphi x Eff

Note that PS expressed as watts = PS x 0.986 x 746

so Eff = PS / (V x I x cosphi) 1.5 x 0.986 x 746 / (220 x 9.65 x 0.78) = 66.6%

If the above is wrong someone will be along shortly :))

For the motor you have assume an efficiency of < 66% and do the calculation.

To calculate power you’d need an accurate model of the motor and its load.
By active power I presume you mean actual electrical input power? That
will be the sum of copper losses, iron losses, windage, friction and load mechanical power

Do you have the nameplate from the actual motor in question? That will show the power factor