BE1-50/51B - Maintenance
6-1
CAUTION
Substitution of printed circuit boards or individual components does not necessarily
mean the relay will operate properly. Always test the relay before placing it in operation.
SECTION 6 • MAINTENANCE
GENERAL
BE1-50/51B Overcurrent Relays require no preventive maintenance. However, periodic checks should be
performed according to scheduled practices. A recommended periodic test is provided in this section. If the
relay fails to function properly and in-house repair is considered, contact the Customer Service Department of
the Power Systems Group, Basler Electric, for a return authorization number prior to shipping.
IN-HOUSE REPAIR
In-house replacement of individual components should be performed by qualified technicians.
When complete boards or assemblies are needed, the following information is required.
1. Relay model number
2. Relay serial number
STORAGE
This protective relay contains long life aluminum electrolytic capacitors. Life in excess of 20 years may be
expected if the storage temperature does not exceed 40
C (72
F).
PERIODIC TESTS
General
All relays should be tested periodically to identify and correct any problems that are found.
Single phase relays such as the BE1-50/51B-105 are normally used in groups of four (three phase and ground)
on the protected circuit. Only three are required at any one time to provide complete protection. The fourth one
assures that protection is maintained even if one relay failed.
This protection scheme also allows one unit at a time to be withdrawn from service for testing purposes without
loosing protection during the test. Refer to Section 5 for recommended test setups.
Periodic Test
Periodic testing should consist of the following procedures.
Step 1. Verify that the instantaneous pickup is within ±2% of the value set on the dials. Pickup occurs when the
INST output contacts close.
Step 2. Verify that the time pickup is within ±2% of the value set on the dials. Pickup occurs when the LED turns
ON.
