9171300990 Rev R
BE1-87T Installation
4-17
Figure 4-18. Control Circuits: Three-Phase, Three Input (Sensing Input G), Output E
RELAY DISASSEMBLY
Precautions
The following procedures require the removal and handling of the internal printed circuit boards. Figure 4-
19 shows the location of major components and assemblies. Because some of the components are
vulnerable to electrostatic charge, the following precautions should be observed.
CAUTION
1. Always remove power from the BE1-87T by removing the connection plugs before
removing or installing a printed circuit board.
2. Always neutralize static body charge before placing a printed circuit board on—or
removing one from—metal surfaces. This can be accomplished by placing your hand
on the metal surface before handling the boards.
3. Never hand a printed circuit board to another person whose static body charge has
not been neutralized.
4. Testing or troubleshooting should always be done on a conductive and grounded
(static-controlled) surface.
5. Never test printed circuit boards with an ohmmeter. The test current from the
ohmmeter may exceed component ratings.
6. Printed circuit boards or integrated circuits should be transported only in electrically
conductive containers. The use of ordinary plastic bags may result in damage from
static charge buildup.
Circuit Board Removal Procedure
Step 1
.
Remove the front cover and connection plugs.
CAUTION
To prevent possible false tripping, the upper connection plug should be in place prior to
removing or installing the lower connection plug.
Step 2.
Withdraw the cradle assembly (see Figure 4-19).
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