OL_P1254 Model (1) - TECO-Westinghouse Motor Company

when, on shutdown, the falling water column tends to drive the pump in the reverse direction.In normal operation, the ratchet pins are lifted by the ratchet teeth and are held clear bycentrifugal force and friction as the motor comes up to speed. When power is removed, thespeed decreases and the pins fall. At the instant of reversal, a pin will catch in a ratchet toothand prevent backward rotation.5.8.2The service life of ratchet pins depends not only on the reverse shock load between the pin andratchet tooth when pump stopped but also the frequency of pump starting and stopping while inservice. Provided that the pins are deformed due to this reverse shock load, then the up anddown motion of the ratchet pins could be sluggish or jammed and that unusual noises shall arise.The recommended replacement period for these ratchet pins is every three (3) years. If thereverse shock load is greater than 30% of motor rated torque or the starting frequency is morethan twice per day, then the replacement period should be halved.ATTENTION!The check valve and stop valve in the discharge line should be regularly inspected andmaintained to assure the normal function of these valves. This is important to protect thepump and motor from damage and increase the service life of the N.R.R. mechanism.Fig. 18SECTION A-AITEMNAME104 RATCHET214 BEARING SEAT402 EXTERNAL FAN704 RATCHET PIN CARRIER816 RATCHET PIN30