Cleaning, checking and setting door interlocks and operator
Oiling rails and checking elevator shoes wear
Worn car shoes may cause problems, such as:
- serious damage to door operator and interlocks
- missing elevator position signals
- car safety brake activation
Oil level in the hoist machine
Cheking SOS devices
Checking the hoist machine brake
An old single speed elevator can not perform a perfect floor leveling. However the brake should be set as best it can.
Oil loss from piston and hydraulic valves
A small oil loss is a normal issue; however, if you cut off the power supply, the elevator should move down by 120 millimeters or less per hour (Italian safety standards).
Ropes and drive sheave grooves
Cleaning and lubrication is important for a long life of ropes and sheave grooves; this issue is often ignored by elevator maintenance workers. Worn ropes feature a smaller size due to traction. Size reduction and grooves wear may cause excessive slip between ropes and drive sheave. Many elevator accidents are caused by rope slip. When you start to see metal filings near the hoist machine, the ropes should be replaced and the sheave grooves should be turned.
Electrical insulation resistance
An insulation failure may cause serious problems to the elevator control system. If a wire makes contact with the metal frame, the overcurrent protection cuts off the control system. But if two wires get in contact each other, a safety switch may be bypassed. This danger is often underestimated.
During its early life, an elevator features an high probability of fault. This is a normal fact, indeed the early life of an elevator is a sort of trial stage. In after years the probability of fault should decrease, if the elevator maintenance company performs a good job and the equipment is used properly.