Motor Power

on . Posted in Motor

Motor power refers to the amount of power or energy that a motor can generate and deliver to perform mechanical work.  The motor power indicates the capability of a motor to convert electrical energy into mechanical energy and drive a load or perform a specific task.  In the context of electric motors, the power rating is an essential specification that users consider when selecting a motor for a particular application. The power requirements depend on the type of work the motor needs to do, the speed at which it needs to operate, and the torque (rotational force) it must provide.

there are different types of motor power

  • Input Power  -  This is the electrical power supplied to the motor.  It represents the power consumed by the motor from the electrical source.
  • Output Power  -  This is the mechanical power delivered by the motor to the driven equipment or load.  It takes into account factors like efficiency and is also measured in watts or kilowatts.
  • Rated Power  -  The power at which a motor is designed to operate optimally and efficiently over an extended period.  It is often a key parameter in motor specifications.

Understanding motor power is used to matching the motor to the specific requirements of a given application, ensuring that the motor can handle the mechanical workload efficiently and reliably.


Motor Power Input formula

\( P_{in} =  I \; V \; PF  \)     (Motor Power Input)

\( I =   P_{in} \;/\; V \; PF \)

\( V =   P_{in} \;/\; I \; PF \)

\( PF =  P_{in} \;/\; I \; V \)

Symbol English Metric
\( P_{in} \) = output power \(W\) \(kg-m^2\;/\;s^3\)
\( I \) = current \(A\) \(C\;/\;s\)
\( V \) = voltage applied \(V\) \(kg-m^2\;/\;s^3-A\)
\( PF \) = Power Factor \(dimensionless\)


Motor Power Output formula

\( P_{out} =  \tau \;/\; \omega \)     (Motor Power Output)

\( \tau = P_{out} \; \omega  \)

\( \omega =  \tau \;/\; P_{out} \)

Symbol English Metric
\( P_{out} \) = output power \(W\) \(kg-m^2\;/\;s^3\)
\( \tau \)  (Greek symbol tau) = torque \(lbf-ft\) \(N-m\)
\( \omega \)   (Greek symbol omega) = angular velocity \(deg\;/\;sec\) \(rad\;/\;s\)


Motor Power Formulas

\(V\) = Voltage  -  \(I\) = Amps  -  \(PF\) = Power Factor  -  \(\eta\) = Efficiency  -  \(P\) = Power

To Find Direct Curren Alternating Current
Single Phase Two Phase Four Wire Three Phase
Power \(V \; I \; \%\eta \) \(V \; I \; \%\eta \; PF\)   - \(1.732 \;V \; I \; \%\eta \; PF\)  


Piping Designer Logo 1

Tags: Power Horsepower Motor