Condition monitoring of motorised valve actuators and similar intermittently operated devices

The author describes work done to identify a simple method of measuring the condition of motorised valve actuators and similar intermittently operated power output devices. By analysing the movement as a command is executed, it is possible to derive a signature descriptive of the actuator or system under investigation. This signature can then be compared with subsequent signatures as the device wears, and eventually used to establish the maintenance intervals applicable to a particular duty