Possible faults Causes Possible remedies
Auxiliary drive motor
does not start
Overload at the output
● Reduce the load at the output
Defective auxiliary drive motor
● Repair the motor or replace
Motor brake not released
● Correct the electrical connection of the motor brake
● If required, replace the motor brake
The auxiliary drive mo‐
tor starts, the main
gear unit output shaft
does not turn
Motor direction of rotation incorrect
● Change polarity of motor
Overrunning clutch cage with
sprags incorrectly installed
● Contact Customer Services
● Install the overrunning clutch cage, rotated through 180° -
or replace
Defective overrunning clutch
● Contact Customer Services
● Replace the overrunning clutch
Leaks
Inadequate sealing of the housing
cover or joints
● Seal housing cover or joints
Labyrinth seals oiled up or transport
position incorrect
● Check oil filling
● Clean the labyrinths
Inadequate sealing of the housing
cover or joints
● Check the seals
● Replace, if necessary
● Seal housing cover or joints
Defective rotary shaft sealing rings
● Check the rotary shaft sealing rings
● Replace, if necessary
Oil is foaming in the
gear unit
Preservation agent not completely
drained off
● Change the oil
Oil supply system left in operation
for too long at low temperatures
● Switch off the oil supply system
● Degas the oil
Gear unit too cold in operation
● Switch off the gear unit
● Degas the oil
● Start up without cooling water during cold restart
Water in the oil
● Take test tube sample to examine oil condition for water
penetration
● Have the oil examined by a chemical lab
● Change the oil if necessary
Oil defoamer has run out
● Examine the oil
● Change the oil if necessary
Unsuitable mixture of oils
● Examine the oil
● Change the oil if necessary
Oil escaping from the
gear unit
Inadequate sealing of the housing
cover or joints
● Check the seals and replace if necessary
● Seal housing cover or joints
● Check the compression seals and retighten screws if
necessary
Leaking pipes
● Check the pipes, and replace or seal if necessary
Oil supply system mal‐
function
-
● Read the operating instructions for the oil supply system
Maintenance
8.4 Possible faults
REDUREX Gear unit 5200en
Operating Instructions 03/2019 101
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