Electronic Trip Molded Case Circuit Breakers
Section
2—MICROLOGIC®
Trip Systems Based on LE, LX, LXI, ME, MX, NE, NX, PE and PX Circuit
Short-time Trip
Functions
The short-time pickup switch value (multiplied by the ampere rating) sets the short-circuit current level
at which the circuit breaker will trip after the set SHORT-TIME DELAY.
Short-time Delay
The short-time delay switch value sets the length of time the circuit breaker will carry a short circuit within
the short-time pickup range. The delay (based on 12 times the ampere rating, P) can be set to four positions
of I2t ramp operation (I2t IN).
06023025
Short-time Pickup
.8
.75
5
4
.9
.7
.5
PICKUP
x P
PICKUP
12
4.5
x S
GROUND FAULT
.32
.32
.2
.2
.1
.1
.5
DELAY
.5
DELAY
DELAY
SEC. AT
6xP
FLASH=90%
ON = OVERLOAD
Short-time
Delay
I 2 t OUT
.5
20
24
2
.75
PICKUP
x P
INSTANT.
I 2 t IN
.5
16
3
Short-time
Pickup
.65
.2
PICKUP
x P
SHORT TIME
11
.55
12 .25
3
10
.45
.35
.3
10
4
8
2
LONG TIME
7
5
6
2.5
1.0
8
6
3
.95
.6
SEC. AT
1xS
SEC. AT
12 x P
Instantaneous Trip
Function
The instantaneous pickup switch value (multiplied by the ampere rating) sets the short-circuit current
level at which the circuit breaker will trip with no intentional time delay.
06023014
Instantaneous Pickup
.75
.8
4
.9
.7
5
.5
PICKUP
x P
1.0
8
2
12
PICKUP
DELAY
Instantaneous
Pickup OFF
PICKUP
GROUND FAULT
.32
.32
.2
.2
.1
.1
.5
.5
DELAY
DELAY
SEC. AT
6xP
FLASH=90%
ON = OVERLOAD
Instantaneous
Pickup
I 2 t OUT
.5
20
24
.65
.75
x S
INSTANT.
I 2 t IN
.5
16
2
.55
.2
x P
x P
3
.45
.3
12 .25
3
10
.35
10
4
SHORT TIME
11
7
4.5
5
6
2.5
PICKUP
LONG TIME
8
6
3
.95
.6
SEC. AT
1xS
SEC. AT
12 x P
The instantaneous function will override the short-time function if the INSTANTANEOUS PICKUP is
adjusted at the same or lower setting than the SHORT-TIME PICKUP.
Ground-fault Trip
Functions
Ground-Fault Pickup
The ground-fault pickup switch value (multiplied by the sensor size) sets the current level at which the
circuit breaker will trip after the set GROUND-FAULT DELAY.
Ground-fault pickup values are based on the circuit breaker sensor size only, not the rating plug
multiplier. Changing the rating plug multiplier has no effect on ground-fault pickup values.
The ground-fault delay switch value sets the length of time the circuit breaker will carry ground-fault
current which exceeds the GROUND-FAULT PICKUP level before tripping. Delay can be adjusted with
four positions of fixed time delays (I2t OUT).
06023026
Ground-Fault Delay
.75
.8
5
4
.9
.7
.5
PICKUP
x P
1.0
7
8
PICKUP
24
DELAY
SEC. AT
6xP
FLASH=90%
ON = OVERLOAD
.2
.1
.5
DELAY
SEC. AT
12 x P
3
12
PICKUP
.2
.55
.65
PICKUP
.75
x S
GROUND FAULT
Ground-fault
Pickup
Ground-fault
Delay
I 2 t OUT
.5
.32
20
2
.45
.3
12 .25
INSTANT.
I 2 t IN
.5
16
.35
10
4
x P
SHORT TIME
11
3
10
x P
LONG TIME
4.5
5
6
2.5
2
8
6
3
.95
.6
.32
.2
.1
.5
DELAY
SEC. AT
1xS
19
06/02
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