Avoid actuators with the designation Class A for torques of more than 1000 Nm.
„Inching“ is defined as: „required to occasionally drive the valve to a position between fully open and fully closed.“
Class C (modulating) increases the demands on: „required to frequently drive the valve….”
|Notes for the table can be found in the draft standard:
To a) : One cycle consists of nominal 90o angular travel in both directions ( i.e 90o to open and 90o to close), based on an averaged load of at least 30 % of the rated torque with the ability to transmit 100 % of the rated torque for at least 5 % at each end of travel, with a cumulative operating time not exceeding 15 minutes in one hour.
To b) : One start consists of a movement of at least 1o in either direction, with a load of at least 30 % of the rated torque. The cyclic duration factor ( i.e. the ratio between the running period and total period ) shall not be less than 25 % (e.g. 1 sec. running and 3 sec. resting ).
To c) : One start consists of a movement of at least 1o in either direction, with a load of at least 30 % of the rated torque.