Chuck Yung
EASA Technical Support Specialist
Have you ever repaired a sleeve bearing motor, only to have the customer complain that it leaks oil? Perhaps the motor had a history of oil leaks, and the windings were oil-saturated when you dismantled it. Two-pole machines are especially notorious as chronic oil leakers. The first step toward correcting an oil leak is to identify the cause.
A good place to start is to determine whether the motor has a forced-oil system. If so, check for a metering plate in the oil supply line. The typical metering plate (see figure) has about a 3/32 diameter orifice to meter the volume of oil. Often installed in a pipe union, the metering plate is easily lost when the motor is removed from service. The repairer rarely gets the forced-oil system with the motor. The customer does not recognize that little piece of metal that looks like a conduit knockout, and that tiny hole can t possibly be for oil flow. So it gets thrown away.
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