YOKOGAWA FC400G, User Manual, Page: 78 / 91

< 8. Maintenance >
8-9
IM 12F5A1-01E
8.2.4 Check / Maintenance / Replacement of Motor and Gear
Head
[Procedure for Checking and Maintenance]
At zero calibration time, operate the indicator electrode and check the following. ( once in three
months recommended)
• Check there’s no irregularity in rotation speed of drive shaft. If there’s any irregularity, loose
the load on the shaft by loosening the screws which fix the driven shaft pulley, and recheck.
If there is still irregularity, replace motor and gear head. If the irregularity doesn’t reappear,
check the driven shaft assembly.
• Abnormal sound from gear head (motor).
If there’s any abnormal sound, check the motor / gear head. (In principle, this should be
done by Yokogawa).
Also, approximately once in six months, check the following items as well:
• Motor rated torque and drive torque.
In <CELL> mode, when motor is turned ON/OFF, after the ON command it should quickly
reach speed. Confirm that the difference in speed of rotation between its normal status, and
when load is reduced by loosening screws fixing pulley to driven shaft, is not noticeable.
If operation is still not satisfactory, replace motor and gear head.
[Replacement procedure]
Replacement of motor and gear head should, in principle, be carried out by Yokogawa service.
If you want to do it yourself, the procedure is as follows:
• In principle, replace motor and gear head at the same time as periodic replacement of other
parts. Replace complete motor assembly consisting of both motor and capacitor.
• When replacing motor assembly and gear head, first remove motor mounting plate from
base.
There are no special cautions relating to removal of, or reassembly of, motor assembly and
gear head.
However, the parts such as electrode, rotating contact and drive belt, which are removed to
detach motor assembly mounting plate, should be carefully reassembled, referring to Sec.
8.2.1 through Sec. 8.2.3.
• The terminal board in motor assembly should be set same position of “C1” and “C2 ” printed
on the plate, whose wire color of “C1” is yellow/green and “C2” is pink/black.