YOKOGAWA FC500G, Руководство пользователя, Страница: 30 / 41

<6. INSPECTION AND MAINTENANCE>
6-3
IM 12F5A2-01E
6.1.3 Brush and Slip Ring Checking
CAUTION
Do not touch the brush except when replacement is performed.
When the electrode assembly cover is removed for polishing the indicator electrode or for other
purposes, visually check the slip ring on the rotating shaft and the brush contacting the slip ring
for abrasion.
Further, measure resistance at the contact every six months. On revolving the indicator
electrode, measure the resistance between the brush-securing screws and the part of the
rotating shaft under the slip ring using a multi-meter. A resistance of 500 Ω or less is acceptable.
Brush
Deive shaft
Clamp
Gear head
F6-2.ai
Belt
Slip ring
Rotating shaft
Contact-pressure
adjusting screw
Pulleys
Brush-securing screws
Lock screw
Cell motor
Base
Indicator
(rotating) electrode
Counter
(reference) electrode
Electrode assembly
Holder
Figure 6.2 Indicator (Rotating) Electrode
If the resistance exceeds 500 Ω, clean the slip ring using an cotton applicator soaked with alcohol
with the indicator electrode rotated.
After cleaning, re-measure the resistance and confirm that the resistance is 500 Ω or less. If the
resistance does not decrease below 500 Ω or if abnormalities such as slip ring wear or brush
wear and bending are detected, the slip ring and/or the brush must be replaced.
The following is the replacement procedure: However, in principle, replacement should be
entrusted to Yokogawa service personnel.
(1) Turn OFF the converter power switch.
(2) Remove the electrode assembly cover. Remove the brush. The brush is secured using two
securing screws (one of them also serves for the wiring terminal).
(3) Remove both pulleys of the drive shaft (motor shaft) and the rotating shaft (indicator
electrode mounting shaft) together with the belt. Remove the drive shaft pulley by loosening
two set screws using an Allen wrench of nominal 1.5 mm (accessory). Remove the rotating
shaft pulley by loosening the screw at the tip of the shaft using a flat blade screwdriver, with
an Allen wrench of nominal 2 mm (accessory) inserted in the hole of the rotating shaft for
preventing revolution.
(4) Draw out the slip ring from the rotating shaft and introduce a new slip ring.