GEK-49822
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.
SERVICING
These relays are adjusted at the factory and it is advisable not to disturb the
adjustments.
If, for any reason, they have been disturbed or it is found during
installation or periodic testing that the relay is out of limits, the-checks and
adjustments outlined in the following paragraphs should be observed.
It
suggested
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
inch
end play.
Contact Adjustment
The contacts should have about
inch wipe.
That is, the stationary contact
tip should be deflected about
inch when the disk completes its travel. Wipe
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. Loosen the screw clamping the arm to the shaft and
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. Also, check reset voltage and time as outlined under RESET in the
CHARACTERISTICS section; low reset voltages or long reset times may indicate excessive
friction caused by a worn bearing or by mechanical interference.
*Indicates Revision
20
