Shop Maintenance; Introduction; Cleaning And Inspection; Armature Stop Pin Cleaning - Hitachi PN-150BE Manual

4.

SHOP MAINTENANCE

4.1. Introduction

This section provides the information necessary to perform shop level repairs of the PN-
150BE relays covered in this manual. In general, relays arriving at the shop for repair
have been checked in the field and have been found to perform unacceptably or have
been physically damaged.

4.2. Cleaning and Inspection

Before inspecting the relay and initiating repairs, use a soft cloth to clean the exterior
carefully to remove any dirt or dust that may have collected. A safe cleaning solution of
alcohol and water may be used for removal of accumulated dirt, grease, etc.
Inspect the relay exterior for signs of physical damage, such as cracked or broken
cover, cracked or damaged housing, and damaged and or missing contact block
terminals and indexing pins. If severe damage is found, a careful inspection of the
interior components should be made for obvious physical damage.
Remove the cover and clean the surface between the armature and the pole faces,
especially the stop pin area, using a lint free cloth and alcohol.
Proceed with stop pin and relay contact cleaning, using the following recommended
cleaning materials:
Recommended Cleaning Materials
Dacron cloth covered metal strip
Extra Dacron sleeving for recovering three metal
strips
#4/0 Metallographic paper sheet 9" x 14"
Burnishing tool
Lead pencil, soft (non-oil content)
Distilled Water

4.2.1. Armature Stop Pin Cleaning

The following instructions are for cleaning the armature stop pin (see Figure 4-1). This
procedure should be followed wherever a relay is shopped for failure to meet its
calibration specifications during scheduled field inspection and tests.
1. Insert a clean Dacron Cleaning Tool (N378099) between the stop pin and relay
pole face. Using moderate pressure to hold the armature closed, pull the
cleaning strip back and forth in a circular motion over the stop pin. Continue this
process until it is apparent that no foreign substances are being transferred to the
strip.
2. The next step is to apply a dry lubricant such as graphite (a soft lead, non-oil
content carpenters pencil is suggested) to the relay stop pin and its point of
contact on the pole face.
a. Take a second clean Dacron strip and rub the graphite over both sides of the
strip, liberally impregnating it with graphite to at least half its length.
Copyright 2019
PN-150BE Biased High Efficiency Vital Relay
Order Reference
N378099
J772330
J035215
J397187
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SM 4551L, Rev. 0 1, March 2019 4-3