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PICKUP RANGE
1
2
4
7
10
20
INDUCTION UNIT
The induction unit consists of a conducting disk that passes through the poles of a
permanent magnet and an electromagnet.
suspended shaft, but is restrained in one direction by a spring.
with an alternating current of proper magnitude
electromagnet produces out-of-phase fluxes at its pole faces.
with induced currents in the disk to produce a torque on the disk.
exceeds the restraining force of the spring, the disk begins to rotate at a speed
determined by the magnetic dragging action of the permanent magnet.
to the rotating shaft travels a specific distance (set by the time dial), and makes
electrical contact with a fixed member.
6
Figure
gives the time for the induction unit to close its contacts for various
multiples of pickup current and time dial settings.
to reset from contact closure to the Number
60
seconds.
Burden data for induction unit coils is listed in Table VIa.
are for the minimum tap.
rating) varies (approximately) inversely to the square of the current rating.
following equation illustrates this:
Impedance of
Any Tap at
Tap Amps
TARGET/SEAL-IN UNIT
The Target Seal-in units are dual rated according to the values on the tap plate on
the right hand side of the unit.
the connecting plug, then use one screw from the left plate to select the correct
tap.
Move the screw from the unwanted tap to the left plate.
the mechanical adjustments will not be disturbed.
in
both taps at the same time.
GEK-86105
TABLE V
RATINGS OF HIGH DROPOUT INSTANTANEOUS UNIT
CONTINUOUS
RATING (AMPS)
- 4
- 8
- 16
- 28
- 40
- 8 0
CHARACTERISTICS AND BURDENS
The disk is free to rotate with a vertically
The impedance for other taps at pickup current
:::;
Tap Amps
If the tap selected must be changed, first remove
RATING (AMPS)
1.5
2.5
6
10.5
15
25
(set by the tap position), the
The time required for this unit
10
time dial position is approximately
Minimum Tap
Tap screws should never be left
6
ONE SECOND
35
75
150
288
288
288
When energized
These fluxes interact
When this torque
A
post attached
The impedance values
This will ensure that
(tap
The
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