Home Page Speed-torque Curve Speed-torque Curve
Search By Category
Search By Keyword
Speed-torque Curve

Selection Table of Motor Power 

on Speed-torque Curves

  • Information on this selection table is applicable to a standard motor (a low-voltage three-phase totally enclosed induction motor with a Class-E insulation), but NOT to those frequently started or operational at dynamic load, impact load and other conditions.

  • Required motor power (KW) is calculated from the following formula:

    Required Load Torque 

    Efficiency Rating 


  • The efficiency rating applied in a 2-stage reducer is 95%; the applied efficiency rating for a 3-stage reducer is 92%.

  • Required load torque is determined by its equivalent value when the motor runs at a fluctuating load; in case the duty cycle is uncertain, apply maximum value in required load torque.

  • In general, start-up torque is not considered.

  • Example of Motor Selection:

    For a motor model to be used with 60Hz power supply, a low-speed shaft with 60rpm and maximum load torque of 6 Kg/m,

    Then, required motor power of 0.4KW can be determined according to the value shown on the crossed point between the lines on Y (6.3Kg/m) and X (60rpm) axes.

    Based on the required power of 0.39KW, a suitable motor in this case is an 1/2 model.




1F., No. 40, Ln. 9, Sec. 2, Zhongxing Rd., Wugu Dist., New Taipei City 248, Taiwan
(02) 2981-5999
(02) 2981-9787





Jhan Rong Mechanical Ltd.