Pickup Tests; Time Setting; Standard Instantaneous Unit; High-Dropout Instantaneous Unit - GE IAC66K Instructions Manual

Pickup Tests

The current at which the contacts operate is determined by the position of the tap plug in the tap
block at the top of the relay.
which the unit is not to operate).
When changing the current setting of the unit, remove the connecting plug to short circuit the current
transformer secondary circuit.
then replace the connecting plug.
The pickup of the unit for any current tap is adjusted by means of a spring-adjusting ring.
may be turned by inserting a screw driver in the notches around the edge.
current of the unit may be brought into agreement with the tap setting employed, if for some reason, this
adjustment has been disturbed. This adjustment also permits any desired setting intermediate between the
various tap settings to be obtained.

Time Setting

The setting of the time dial determines the length of time the unit requires to close its contacts when
the current reaches a predetermined value.
the dial is set on 10, the disk must travel the maximum amount to close the contacts and therefore this
setting gives the maximum time setting.
The primary adjustment for the time of operation of the unit is made by means of the time dial.
further adjustment is obtained by moving the permanent magnet along its supporting shelf; moving the magnet
toward the disk shaft decreases the time, while moving it away increases the time.

STANDARD INSTANTANEOUS UNIT

Select the current above which is desired to have the instantaneous unit operate and set the adjustable
pole piece so that the top of the hexagon head is even with the desired calibration oo .. .the scale. To raise or
lower the pole piece, loosen the locknut and turn it up or down and then tighten in position.
The contacts should be adjusted to make at about the same time and to have approximately 1/32 inch wipe.
This adjustment can be made by loosening the screws holding the stationary contacts and moving the contacts
up or down as required.
HIGH-DROPOUT INSTANTANEOUS UN IT
The high-dropout, instantaneous unit is similar to the standard, instantaneous unit except it has no
target and dropout current is approximately 80 percent of the pickup current.
high dropout unit.
The adjustable core (A) sets the pickup level.
pickup, while turning the core up (counterclockwise, top view) increases the pickup.
turn the core, the locknut (B) must be loosened.
When loosening or tightening the locknut, the sleeve (C) to which the shading ring (D) is attached must be
held to prevent it from turning.
the quietness of operation in the
dropout at the m inimum setting. Should it be necessary to change the dropout setting, the sleeve (C) to which
is
t he shading ring (D)
prevent the sleeve and shading ring assembly from being loosened.
The unit will pickup at the scale-plate marking plus or minus 15 percent with gradually applied current.
The mean air gap should be approximately l/16 inch, the contact gap approximately 3/32 inch, and the
contact wipe approximately 1/32 inch.

TARGET AND SEAL-IN UNIT

For trip coils operating on currents ranging from 0.2 up to 2.0 amperes at the minimum control voltage,
set the target and seal-in tap screw in the 0. 2-ampere tap.
For trip coils operating on currents ranging from 2 to 30 amperes at the minimum control voltage, place
the tap p l ug in the 2-ampere tap.
Screw the tap plug firmly into the tap marked for the desired current (below
Next, screw the tap plug into the tap marked for the desired current and
The contacts are just closed when the dial is set on zero.
Rotation of the shading ring sets the dropout level and thereby determines
picked up position.
attached must always be turned in the clockwise direction (top view) .
GEI-44233
Turning the core down (clockwise, top view) lowers the
After adjusting the core, the locknut must be retightened.
The core been
has
9
By turning the ring, the operating
Fig. 5 is a picture of the
Before attempting to
factory set to obtain 80 percent
This will
The ring
When
However,