Instantaneous Unit; Servicing; Time Overcurrent Unit; Disk And Bearings - GE IBCG51M A Series Instructions Manual

Ground directional overcurrent relays
Hide thumbs Also See for IBCG51M A Series:
Table of Contents

Advertisement

INSTANTANEOUS UNIT

Check that the instantaneous unit picks up at the desired current level, as outlined
in the ACCEPTANCE TESTS and the INSTALLATION TEST sections.
These relays are adjusted at the factory and it is advisable not to disturb the
adjustments.
installation or periodic testing that the relay is out of limits, the-checks and
adjustments outlined in the following paragraphs should be observed.
that this work be done in the laboratory.
TARGET AN0 SEAL-IN UNIT
Repeat the visual and mechanical inspections and the pickup and dropout current
checks as outlined in the ACCEPTANCE TESTS section.

TIME OVERCURRENT UNIT

Disk and Bearings

The jewel should be turned up until the disk is centered in the air gaps, after
which it should be locked in this position by the set screw provided for this purpose.
The upper bearing pin should next be adjusted so that the disk shaft has about1/64 inch
end play.

Contact Adjustment

The contacts should have about l/32 inch wipe.
tip should be deflected about l/32 inch when the disk completes its travel. Wipe iS
adjusted by turning the wipe adjustment screw thereby adjusting the position of the
brush relative to the brush stop.
When the time dial is moved to the position where it holds the contacts just
closed, it should indicate zero on the time-dial scale. If it does not and the brushes
are correctly adjusted, shift the dial by changing the position of the arm attached
the shaft just below the time dial.
turn the arm relative to the shaft until the contacts just make for zero time-dial
setting.
Characteristics Check and Adjustments
Repeat the portions of the ACCEPTANCE TESTS section that apply to the time
overcurrent unit.
CHARACTERISTICS section; low reset voltages or long reset times may indicate excessive
friction caused by a worn bearing or by mechanical interference.
*Indicates Revision
If, for any reason, they have been disturbed or it is found during
Also, check reset voltage and time as outlined under RESET in the
GEK-49822

SERVICING

That is, the stationary contact
Loosen the screw clamping the arm to the shaft and
20
It

Advertisement

Table of Contents
loading

Table of Contents