Description - GE DIAC 66K Instruction Manual

GEK-106261 3 CALCULATION OF SETTINGS
GEK-106261 3 CALCULATION OF SETTINGS

3.1 DESCRIPTION

When replacing IAC 66K relays, review the time current curves of the digital relays to verify that they conform
to the relays being replaced. In some cases it may be necessary to redo the coordination study to assure coor-
dination with other devices.
The base time of the Definite Time Curve is 1 second. The base time is multiplied by the time dial to provide
the actual operating time. The default or lowest time dial setting for the Definite Time Curve is 0.1.
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The I T curve has a K value of 250 @ time dial of 1. The range is from 25 to 2475 in steps of 25 set by the time
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dial. The default or lowest time dial setting for the I T curve is 0.1.
Pickup for the TOC/ Inst unit is settable from 0.5 to 15.9 amps in 0.1 amp increments for the 5 amp model, and
0.1 to 3.18 amps in 0.02 amp increments for the 1 amp model, a setting of 0 disables the TOC element. The
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time dial can be set from 0.5 to 9.9 in 0.1 increments on both the 5 amp model and the 1 amp model. The only
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exception is for the Definite Time and I T curves where 0.1 is the minimum value.
The IOC function is settable from 1 to 159 amps in 1 amp increments for the 5 amp model, and 0.2 to 31.8
amps in increments of 0.2 amps for the 1 amp model. Setting the pickup to 0 disables the IOC element. Both
models have an IOC delay adjustment from 50 to 400 milliseconds in 25 millisecond steps.
The formula is:
IOC delay (in milliseconds) = DS × 25 + 25
where DS is setting on IOC delay dial.
The TOC reset characteristic can be controlled from the front panel. The TOC reset can be set to "timed reset"
which emulates the characteristic of an induction disk relay, or "instantaneous reset" where the reset is fixed at
40 to 50 milliseconds.
The system frequency can be set for 50 or 60 Hz controlled from the front panel.
The High Set Standard (EM) Instantaneous unit pickup range can be adjusted continuously over a four to one
range by using the adjustable pose piece. When the top of the core is lined up with the calibration stamping, an
approximate value of pickup can be determined. Dropout is at least 40 to 50 percent of pickup.
GE Power Management DIAC Type 66K Digital Overcurrent Relay 3-
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