GE P742

Maintenance
P74x/EN MT/N
a7
MiCOM P74
1, P742, P743
(MT) 11-
1
MT
CONTENTS
1. MAINTENANCE 3
1.1 Maintenance period 3
1.2 Maintenance checks 3
1.2.1 Alarms 3
1.2.2 Opto-isolators 3
1.2.3 Output relays 3
1.2.4 Measurement accuracy 3
1.3 Method of repair 4
1.3.1 Replacing the complete relay 4
1.3.2 Replacing a PCB 5
1.4 Recalibration 19
1.4.1 P74x relay 19
1.5 Changing the relay battery 19
1.5.1 Instructions for replacing the battery. 19
1.5.2 Post modification tests 19
1.5.3 Battery disposal 19
1.6 Cleaning 20