YOKOGAWA FC400G User Manual

< 8. Maintenance >
8-7
IM 12F5A1-01E
8.2.3 Check/Maintenance/ReplacementofDrivenShaft
Assembly
[Checks and Maintenance]
At zero calibration time, operate the indicator electrode and check the following (once in three
months recommended )
• Check if noisier that usual, or if vibration or non - continuous noises.
If sound is abnormal, driven shaft assembly may be bad, or problem may be in motor. Stop
electroderotation,checkifbearingatbottomofdrivenshaftisgone(seesix-monthlycheck
below).
• Check if vibration in driven shaft or indicator electrode.
Usually the bushing (bearing) at the bottom is the cause. Stop the rotation and check (see
six-monthlycheckbelow).
• Manuallyturnthedrivenshaftandconrmthatit’sassmoothasusual.
Ifthereisanyclatter,ifdrivebelthascomeo󰀨orshaftdoesnotrotateeasily,orarubbing
noise is evident, promptly replace the driven shaft assembly.
[Replacing the driven shaft assembly]
If the bearing has become bad, replace the driven shaft assembly. In principle,this should be
done by Yokogawa’s service facility.
If the user wishes to replace it, the procedure is as follows:
Items (1) to (9) relate to disassembly, and items from (10) onwards relate to reassembly.
(1) Shuto󰀨thepowerfedtotheFC400G,thenplacetheelectrodemechanismblockinthe
maintenance position then remove the cover from the electrode part.
(2) Remove indicator electrode and counter electrode.
To remove the indicator electrode, inset the supplied Allen wrench into the socket of the
driven shaft, to stop it from rotating.
Disconnectthethreewiresconnectedtothecounterelectrode,nextloosenandremovethe
clamp holding the electrode in its holder.
(3) Remove the drive belt. Remove the drive belt with pulleys all together installed onto the
drive shaft.
(4) Remove the rotating contact out of the driven shaft.
(5) Remove the dust protection plate installed to prevent drive belt shavings to enter the
electrode holder in the driven shaft assembly by loosening the two screws.
(6) Removetheplatewhichholdsdrivenshaftassemblyinplacewithtwoscrews.
(7) Take out the defunct driven shaft out of the motorremove it from motor mounting plate. The
place where the electrode holder base is inserted contains an O-ring. This O-ring and the
counterelectrodexingclampcanbereused.
Note: Even if the O-ring (part no. Y9115XB) is not damaged, it is recommended to replace it after 3 years use.
Thefollowing,fromitem(8)belowonwards,istheprocedureforreassembly.
When reassembling, observe the following cautions:
• Cleananydirto󰀨partsbeforereassembling.
• Adjustdrivebelttensionto4N(0.4kgf).
• When reassembling, make sure that indicator electrode does not make contact with its
base.
(8) Assemblenewdriven shaft assembly on motor mounting plate. First, install the clamp and
O-ringintheelectrodeholderinthedrivenshaftassembly.Next,mountthedrivenshaft
assembly on the motor mounting plate, taking care not to allow the O-ring to protrude from
the hole in the base.
(9) Mount plate that holds driven shaftassemblyinplace.Conrmthatfourpinsonplate
surround electrode holder and, as a temporary measure, loosely tighten the two screws in

YOKOGAWA FC400G Specifications

General

Brand	YOKOGAWA
Model	FC400G
Category	Measuring Instruments
Language	English