Type B Vital Relays - Alstom

Preventive Maintenance
4.5.1. AC Light-Out Relay Test
The AC Light-Out Relay is available in two coil configurations:
• A pair of low resistance coils wired in series
• A low resistance coil and high resistance coil
To obtain DROPAWAY, PICKUP, and WORKING current values follow the procedure in
Table 4–7.
Table 4–7. AC Light-Out Relay Test Procedure
Step
Procedure
1 Perform the visual inspection procedure in Table 4–2.
2 Saturate the relay coils with current at the value shown on the Relays ED sheet.
Coils are connected in series unless otherwise indicated.
3 Slowly decrease current and obtain DROPAWAY, which is the value at which
the back contacts just make.
4 Open circuit.
5 Close circuit and slowly increase the current to obtain PICKUP, which is the
value at which the front contacts just make.
6 Continue to slowly increase the current to obtain WORKING current, which is
the value at which the armature is against the front stop. Frequently the PICKUP
and WORKING current values are the same.
P1457, Rev. Nov/07 4–11 Alstom Signaling Inc.