We’re currently working with a long-standing offshore client to carry out the urgent test and calibration of an overspeed switch from their #Detroit 8V71 turbine starter.
The trip test speed was unknown by the operator, and with all engine protection devices, it is vital to ensure it will work safely and effectively when called upon.
To avoid actually overspeeding the engine (or worse, should the switch fail), the switch was sent to us to carry out the testing on our test bench.
Once the switch was set up on our rig, we were able to calculate the current trip speed and test that the overspeed triggered at the correct point, which would close the air flap valves, and light the bulb we use for additional visual notification.
Another advantage of this test is that the overspeed can be set at the exact point, again removing the requirement to actually overspeed the engine.
We recommend the overspeed is checked annually so you know you can rely on it in an emergency.