Type B Vital Relays - Alstom

Preventive Maintenance
4.3. PREVENTIVE MAINTENANCE TOOLS
See Appendix C for a summary of B relay tools.
A specific wrench is used to turn the terminal nut on the current test post to open the
coil circuit. Figure 4–1 shows a Spanner Nut Wrench (also called the "E" post wrench,
P/N 55393-003-01).
Figure 4–1. Spanner Nut Wrench
The Shop Test Rack, P/N 56573-002-01, is used to test relays in the shop. See
Appendix C for details about the Shop Test Rack.
Electrical tests for operating values on Type B2 two element vane relays are made with
the Vane Relay Test Unit, P/N 20182-111-01. See Appendix C for details about this test
unit.
4.4. RELAY INSPECTION
All Type B relays must be visually inspected prior to performing electrical tests. Each
Type B relay is in a clear plastic case and the parts to be inspected can be seen with
the cover installed and sealed.
WARNING
BREAKING THE RELAY COVER SEAL VOIDS THE WARRANTY ON
THE RELAY.
Visual inspection includes checking contacts for damage or misalignment, corrosion or
other contamination of parts, loose parts inside cover, broken seal, cracked, broken or
discolored covers and wear particles on inside of cover. The inspection procedure
provided in Table 4–2 describes how to inspect a typical B1 relay. Table 4–3 describes
how to inspect a vane relay. Table 4–4 is a general relay inspection procedure
applicable to all other relays.
NOTE
If any damage is detected, the relay must be removed from service and
replaced.
P1457, Rev. Nov/07 4–3 Alstom Signaling Inc.