Sun Yeh Electrical OM Series - 3.4 Actuator Sizing; 3.5 Duty Cycle

Quarter -Turn Electric Valve Actuator【OM Series】 Sun Yeh Ele. Ind. Co., Ltd. | 2021.11
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3.4 Sizing
a. The actuator shall be sized to ensure that its torque output meets the load requirements of
valve and its ability to overcome the required duty cycle of application (As a MINIMUM,
a 30% safety factor is suggested for the calculation of torque requirement).
 If the maximum torque of 5” valve is 80 Nm  80 × 1.3 (safety factor) = 104 Nm
104 Nm < 150 Nm (OM-3) OK!
104 Nm > 90 Nm (OM-2) Not OK!
b. In cases where the actuator does not fit directly onto the valve, a mounting kit is required.
Please ensure the bracket and coupling are properly designed and manufactured to
withstand the torque output of the actuator.
3.5 Duty Cycle
 The standard duty cycle for OM series is 30% and 50% or 75% is for option. The duty
cycle is the relationship between the running time and resting time. It is calculated as
below:
Duty Cycle = x100 %
Rest Time (Sec)=
 If the running time for OM-2 is 15 sec, 30% duty cycle, the rest (off) time shall be
calculated as below:
15 × [ ( 1–30%) / 30% ] = 35 The rest time will be 35 sec.
 If the running time for OM-2 is 15 sec, 75% duty cycle, the rest (off) time shall be
calculated as below:
15 × [ ( 1–75%) / 75% ] = 5 The rest time will be 5 sec.
Note: For higher duty cycles, choose the 75% duty cycle.
One cycle consists of open-rest-close-rest.
Running Time (Sec)
Running Time (Sec) + Rest Time (Sec)
Running Time (Sec) x (1- Duty Cycle)
Duty Cycle