Uneven tension in governor rope

• Causes

1. Wear and tear with time or due to poor specification
2. Irregular condition checking as never used except emergency

• Diagnostic/testing method

The general condition of the speed governor, governor rope and diameter, tripping mechanism and governor switch and governor data plate shall be inspected while cut off the power. With power on, the overspeed governor shall be inspected under normal running conditions.

Spring balance or other suitable equipment shall be used to ensure the governor ropes are equally tensioned (SS550).  According to EN 81-50, requirement testing of tripping by breakage of suspension means by actuating the mechanisms for tests without entering the well, and maximum force to actuate is 400 N.

• Good practices

The breaking load of overspeed governor ropes shall have a minimum of 8 to the tensile force produced when tripped. When tripped, the breaking load of the rope shall be related by a safety factor of 8 to the tensile force produced in the overspeed governor’s ropes.

Breakage or slackening of ropes can cause the motor to stop by means of an electric safety device. The governor rope diameter shall be at least 6 mm (SS550). The governor ropes shall be made from iron, steel, monel, metal, phosphor bronze or stainless steel (ASME A17.3-2008).

• Corrections

The overspeed governor shall be inspected in interval of 6 months, which the maintenance works should cover:

1. Visual inspection of governor ropes to see if there is damaged wires, deformations, dirt, and grease. If the ropes show any signs of wearing, they are shall be replaced by qualified personnel;
2. Clean the ropes if they are greasy and dirty;
3. Inspect the governor groove and if they are in a gad condition, the groove shall be replaced immediately as the ropes might break when the governor trips;
4. Visual inspection of tension spring, seal, and general state. The tripping speed has to be checked, ensuring its accordance to the standards