Set A Set A
Set B
Trigger event
PROTECT ION TR I P UNI TS
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Set A
Trigger event Trigger event
t t t
IEC 60947-4-1 Table 2 IEC 60947-4-1 Table 2 IEC 60947-4-1 Table 2 IEC 60947-4-1 Table 2
Trigger event
t
I I I
t t t
I
Ij/Is
t t
Ij/Is Ij/I
ti/tj
f f f
Ij/Is
ti/tj ti/tj
ti/tj
U Protection against phase loss and/or unbalance This can be implemented when the motor must be promptly protected owing to the absence of a phase. The protection trips if the r.m.s. value of at least one of the phase currents drops below the level equal to 0.1 times the rated current of the trip unit and a second phase exceeds 0.25 times the rated current. The circuit-breaker is opened if the current value fails to rise above this level within 2 sec. During start-up, the tripping time of the protection is the lowest value between 2 sec or half the minimum time of the start-up class. The protection has a “start-up” stage starting from the moment the current exceeds 0.25xIn to the moment the minimum time of the selected trip class is reached. UC Undercurrent protection This function protects the motor from operating in conditions where the load is reduced or null. The cir- cuit-breaker is opened if all the phases remain below the threshold setting I9 for delay-time t9. The protec - tion has a “start-up” stage from the moment the current exceeds 0.25xIn to the moment the minimum time of the selected trip class is reached. IU Protection against phase unbalance This unit is used when a motor needs to be protected against differences in the currents circulating in the phases. Threshold setting I7 defines the maximum level of difference between each phase and the mean value of the three phases. If a phase differs more than its set level from the mean value, the protection opens the circuit-breaker once its time-delay setting (t7) has elapsed. The protection is activated only if all three phase currents exceed 0.25xI1. During the start-up phase, the tripping time is the lowest value be - tween t7 or half the minimum time of the start-up class. The protection has a “start-up” stage from the moment the current exceeds 0.25xIn to when the minimum time of the selected trip class is reached. PTC Temperature protection In its initial configuration, this trip unit is set up to receive an incoming signal from a PTC sensor installed on the motor. The operating thresholds of the protection are defined in accordance with the Standard IEC 60947-8. If the threshold is exceeded, the trip unit opens the circuit-breaker after a 1 sec time-delay. Ekip CI Contactor Interface for motor protection The breaking capacity of a contactor is definitely lower than a circuit-breaker, but with a number of possible operations consistently higher than those of the breaker (approx. 1,000,000): motor protection and opera - tion are thus optimized when these two devices are used in conjunction with each other. In its initial config- uration, the trip unit is set for operation in Normal mode, activating the contactor by means of the Ekip CI module if one of the protections trip (with the exception of protections I and G). If the configuration is changed from Normal to Heavy, the trip unit opens the circuit-breaker directly with- out transmitting the command to the contactor. An auto-reset function allows the actuation status of the Ekip CI to reset automatically after the contactor has tripped owing to the L function, once an adjustable time from 1 to 1000s has elapsed. Auto-reset can occur only in Normal mode. A BACK UP function is also available and deals with situations where an opening command transmitted to the contactor via module Ekip CI has not been successful. In this case, the EKIP M Touch LRIU trip unit sends an opening command to the circuit-breaker after waiting for the set time Tx. The actuation time of the contactor given by the manu- facturer must be considered when the time-delay setting Tx is entered. The function is active with an auxil- iary supply.
f
t t t
Iu
t
Iu I
tu
f f f
Iu
tu t
tu
t t t
f
Iuc
t
Iuc I
tuc
f f f
Iuc
tuc t
tuc
f
t t t
I7
t
I7 I
t7
f f f
I7
t7 t7
t7
t t t
f
PT100
t
PT100 PT100
f f f
PT100
f
Ekip M Touch LRIU
Ekip M Touch LRIU Ekip Touch LRIU
Ekip M Touch LRIU
Contactor
Contactor Contactor
Contactor
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