GE AKR-30 Series Maintenance Manual page 73

1 3.2 SERIES OVERCURRENT TRIPPING
DEVICE Ec-1
Each series overcurrent tripping
molded case and mounted by screws and a bracket to the lower
part of the pole unit base.
Refer to Fig. 1 01 for the discussions below.
13.2.1 SHORT TIME-DELAY TRIPPING
The armature (7) is restrained by calibrating spring (8). After
the magnetic force produced by
Left Side VIew Showing
Short Time Delay Mechanism
.
1 Coil
Series
2. Magnet
3. Pallet
4. Pinion
5. Escape Wheel
6. Driving Segment
7. S.T.D. Armature
is enclosed in a
device
overcurrent condition over-
an
9
4
Front VIew Showing
Mounting Bracket
8. S.T.D. Calibration Spring
9. Trip Paddle Adjusting Screw
10. L.T.D. Armature
L
1 1 . T.D. or Low-set lnst. Calibration Spring
1 2. lnst. Trip Spring (High
1 3. Spring Holder
1 4 . C&libration Clamp
RG. 1 01 SERIES OVERCURRENT TRIPPING DEVICE EC-1
comes this restraining force, the armature movement is further
retarded by an escapement mechanism which produces an in­
verse time delay characteristic. The mechanism is shown on
Fig. 1 01 .
1 3.2.2 LONG TIME-DELAY TR
The armature (1 0) is restrained by the calibration spring (1 1 ).
After the magnetic force produced by an overcurrent condition
overcomes this restraining force, the armature movement is fur­
ther retarded by the flow of silicone oil in a dashpot, which pro­
duces inverse time delay characteristic. The mechanism is
an
shown on Fig. 1 0 1 .
Right Side VIew Showing
Long Time Delay Mechanism
Set)
Nut
P
I PIN G
1 5. Plunger
1 6. Cylinder
1 7. Calibration Plate
1 8. Trip P addle
1 9. Trip Arm
20. Clamping Bracket
73