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PowerPact H-, J-, and L-Frame Circuit Breakers
Motor Circuit Protection
59
02/2016
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All Rights Reserved
Additional Technical Characteristics
Table 55: Additional Technical Characteristics
Phase unbalance
An unbalance in three-phase systems occurs when the three
voltages are not equal in amplitude and/or not displaced 120°
with respect to each other. It is generally due to single-phase
loads that are incorrectly distributed throughout the system and
unbalance the voltages between the phases.
These unbalances create negative current components that
cause braking torques and temperature rise in asynchronous
machines, thus leading to premature aging.
Phase loss
Phase loss is a special case of phase unbalance.
• During normal operation, it produces the effects mentioned
above and tripping must occur after four seconds.
• During starting, the absence of a phase may cause motor
reversing, i.e. it is the load that determines the direction of
rotation. This requires virtually immediate tripping (0.7
seconds).
Starting time in compliance with the class (Micrologic 2 M)
For normal motor starting, Micrologic 2 M checks the conditions
below with respect to the thermal-protection (long-time) pick-up
FLA:
• current > 10% x FLA (motor-off limit)
• overrun of 1.5 x FLA threshold, then return below this
threshold before the end of a 10 s time delay.
If either of these conditions is not met, the thermal protection
trips the device after a maximum time equal to that of the
selected class. Pick-up FLA must have been set to the current
indicated on the motor rating plate.
Starting time in compliance
with the class
(Micrologic 2 M)
For normal motor starting, Micrologic 2 M checks the conditions
below with respect to the thermal-protection (long-time) pick-up
FLA:
• current > 10% x FLA (motor-off limit)
• overrun of 1.5 x FLA threshold, then return below this
threshold before the end of a 10 s time delay
If either of these conditions is not met, the thermal protection
trips the device after a maximum time equal to that of the
selected class.
Pick-up FLA must have been set to the current indicated on the
motor rating plate.
1 to 200 s
Return
Overrun
FLA
1.5 FLA (Micrologic 2-M)
or Ilong (Micrologic 6 E-M)
10 % FLA
Motor-Off zone
Starting
Time
Long
Start Time
Limit
Motor Starting and Long Starts
Unbalance of Phase Currents and Voltages
I
B
(V
B
)
I
C
(V
C
)
I
A
(V
A
)
Table 56: L-Frame Electronic Trip Unit Magnetic Only 3 Pole, 600 Vac, 50/60 Hz—Three
Device Solutions
1
1
Three-device solutions are the traditional solutions: motor circuit protector plus motor starter plus overload relay.
Sensor Rating
Trip
Unit
Adjustable
2
Trip Range (A)
2
UL magnetic trip tolerances are -20%/+30% from the nominal values shown.
G-Interrupting
Cat. No.
J-Interrupting
Cat. No.
L-Interrupting
Cat. No.
R-Interrupting
Cat. No.
PowerPact
L-Frame
400
1.3 M
500–1200% LGL36400M37X LJL36400M37X LLL36400M37X LRL36400M37X
600 500–1200% LGL36600M37X LJL36600M37X LLL36600M37X LRL36600M37X