Specifications

TROUBLESHOOTING Document No. DER05105
Effective Date 15 Jul 08 Page 11 of 16
Alarm and Fault Messages
Cause Corrective Action
Solid End Main Bearing High Temperature Fault and Shutdown
Insufficient bearing lubrication Lubricate bearings (refer to DER05023).
Excess grease Remove grease fitting, and direct jet of filtered
compressed air to remove grease.
Incorrect grease Lubricate with recommended grease (refer to
DER05023
).
Defective bearing Replace both main bearings (refer to DER05024).
SPEED SENSOR ADJUSTMENT
Bowl speed is sensed by a proximity switch (speed sensor) that is pulsed by the cam ring as it
rotates beneath the switch. A series of equally spaced holes in the circumference of the cam ring
produce the pulses in the sensor that are used by the PLC to calculate bowl speed. Pulses are
lost if excessive space is present between the switch and cam ring, and insufficient space will
cause the cam ring to strike the switch. Consequently, the gap between the proximity switch and
cam ring is critical.
The sensor is installed in the main bearing pillow block at the solid end of the centrifuge.
Adjustment is performed by turning the switch in or out within the pillow block. To adjust the
speed sensor, proceed as follows:
1. Remove screws securing bowl cover to base, and open cover.
2. Remove screws securing speed and temperature sensor guard to main bearing pillow block
(Figure 5105-1), and remove guard.
3. Disconnect electrical cable from speed sensor (Figure 5105-2).
4. Loosen speed sensor locknuts, and rotate locknuts counterclockwise until several threads are
exposed.
5. Slowly rotate sensor clockwise until bottomed gently against cam ring, and then back out the
sensor 2-1/2 turns.
6. Tighten bottom locknut against pillow block, and then tighten top locknut to secure both
locknuts.
7. Reconnect electrical cable to speed sensor.
8. Close and secure bowl cover.
9. Turn on and test centrifuge for proper operation in accordance with DER04098
.
10. If speed sensor still does not function properly, loosen locknuts, turn sensor clockwise in 1/8-
turn increments until correct speed sensing is evident. Tighten locknuts against pillow block
when sensor operation is restored.
11. Replace speed sensor if adjustment does not produce correct speed indication.
12. Re-install guard over speed and temperature sensors, and secure with screws.