MHS Boilers XenoROL XR40, Инструкция по установке, эксплуатации и обслуживанию, Страница: 68 / 84

XenoROL®
68
MOTOR CONTROLS
INSPECTION
Excessive overheating is indicated by discoloration
of components. Most often, these symptoms are a
sign of loose connections. If left uncorrected this
can eventually cause arcing between components,
leading to destruction of controls. It is, however, not
unusual to find the interior to the MCC quite warm
when it is first opened.
The condition of contacts must be checked on all
contactors and starters that show signs of
overheating to ensure that they are free of dust and
dirt and are not excessively pitted or burned. When
badly burned or worn, the contacts must be
replaced.
In the course of inspecting contact condition, spring
pres-sure should be checked. As contact surface
wears down, spring pressure can be lost because of
the overheating. Contact spring resiliency can
usually be detected by fingertip pressure.
Check for faulty gaskets especially when there are
excessive deposits of foreign materials. Particular
attention should be given to conductive deposits
because they can cause flashovers and premature
component failure when allowed to collect to any
great extent. Either reposition or replace defective
gaskets and clean the control cabinet.
Check overload settings on motor controls. Check
for loose wiring and tighten as required.
CLEANING
When cleaning a control cabinet, it is best to use a
vacuum cleaner rather than compressed air. A
vacuum cleaner removes rather than redistributing
dust and dirt. Com-pressed air can damage and
displace relay contacts and springs.
SENSING SWITCHES
The sensing switches are of two types: retro-
reflective photoeye and proximity switch.
Adjust the retro-reflective type as follows
1. Determine what sizes of target the photoeye
must sense.
2. Adjust for the worst case, usually smallest
item, by loosening photoeye mounting nut and
aligning while making sure photoeye has
unobstructed view of reflector.
3. Move the target in and out of the field of
detection to ensure that the photoeye
energizes and de-energizes.
Adjust the proximity type as follows:
1. Loosen proximity switch mounting bolt and
adjust sensing switch so that the product
passes directly in front of the switch face, as
close to the switch face as possible without
making contact.
2. Check that the proximity switch energizes and
de-energizes as the product passes in front of
the switch face.
3. Tighten the mounting bolt.
WARNING
Before servicing or performing any work in the
motor control panel, disconnect and lockout the
main incoming service. If only the panel
disconnect is off, the incoming side will still be
WARNING
Avoid touching components until they have
had time to cool. Some still may be hot.
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