*(.%
24
CALCULATION OF SETTINGS
When replacing IAC, IFC or SFC re-
lays, review the time current curves of
the digital relays to verify that they con-
form to the relays being replaced. In
some cases it may be necessary to redo
the coordination study to assure coordi-
nation 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 .
The I
2
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 dial.
The default or lowest time dial setting
for the I
2
T curve is 0.1 .
TOC pickup 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 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 exception is for the Definite Time
and I
2
T curves where 0.1 is the mini-
mum 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 in-
crements 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
; IOC delay in milliseconds
= DS x 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.
Summary of Contents for DIAC
Page 29: ...28 FIGURE 18 DIAC and DSFC External Internal Connections...
Page 30: ...29 FIGURE 19 DIFC External Internal Connections...
Page 31: ...30 FIGURE 20 DIAC Panel Mounting and Drilling...
Page 32: ...31 FIGURE 21 DIFC Panel Mounting and Drilling...
Page 33: ...32 FIGURE 21A SURFACE MOUNTING DIFC...
Page 34: ...33 FIGURE 22 DSFC Panel Mounting and Drilling...
Page 42: ...41 FIGURE 27 9819647 8919648 DIAC Front and Rear Views...
Page 43: ...42 FIGURE 28 8919652 8919653 DIFC Front and Rear Views...
Page 44: ...43 FIGURE 29 8919632 8919661 DSFC Front and Rear Views...