General Information
1-4
Timing Accuracy
(51V Functions)
Within ±5% or 50 mSec, whichever is greater for time dial settings of D
greater than 0.1 and multiples of 2 to 40* times the pickup setting but not
over 30 A for 5 A CT units or 6 A for 1 A CT units.
* 3-40 times pickup for the A-curve.
Voltage Restraint: Voltage restraint compares the sensed voltage with the nominal voltage
level. A decrease of the sensed voltage (between 100% and 25% of
nominal) results in a proportional decrease of the time overcurrent pickup
point. When the sensed voltage falls below 25% of nominal, the time
overcurrent pickup point will be 25% of the actual time overcurrent setting
(see Figure 1).
25%
0%
50%
100%
75%
25% 100%50% 75%
Sensed Voltage
Percent of Pickup Setting
D2224-21.vsd
01-31-00
Figure 1-1. Voltage Restraint
Power Supply: Power input (battery)
12 Vdc nominal systems (8 to 16 Vdc)
24 Vdc nominal systems (16 to 32 Vdc)
Power dissipated is 6.5 watts
Inputs: Voltage Sensing Inputs
100 to 480 Vac nominal, 50 to 60 hertz, @ less than 1 VA per phase
1.2 times nominal continuously
1.5 times nominal for 10 seconds
May be: single-phase; three-phase, three wire; or three-phase, four
wire
Current Sensing Inputs
1 or 5 ampere input @ 1 VA per phase
2 times nominal continuously
10 times nominal for 1 second
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