Usually we are used to describe the power of the electronic device wtih a load capacity possessed, but for servo motor system, the main part is the output torque which could guide the relative concepts.  From the notion of the motor driving circuit design, the power is focused especially.  For the purpose we must clarify the relationship among the power, the torque, and the speed as following:

1. Power ( P _W ) = Force ( F ) x Linear Velocity ( V )
2. Force ( F ) = Torque ( T _Nm ) / Radius ( r )
3. Linear Velocity ( V ) = 2 π r x Angular Velocity ( n _RPS ) = ( 2 π r x n _RPM ) / 60 = ( π r x n _RPM ) / 30

• Guide formula 2 and 3 into formula 1, and then we can get:
• Power ( P _W ) = ( T _Nm / r ) x ( π r x n _RPM / 30 ) = ( π / 30 ) x T _Nm x n _RPM

We can transfer the unit of Power from ( P _W ) to ( P _KW ), and then get the following:

• Power ( P _KW ) = { ( π / 30 ) x T _Nm x n _RPM } / 1000
• Power ( P _KW ) = ( 3.1415926 / 30000 ) x T _Nm x n _RPM
• Power ( P _KW ) = ( T _Nm x n _RPM ) / 9549.297 ≒ ( T _Nm x n _RPM ) / 9550

 Following table shows the notion applied into the actual environment: