pag. 8
MDE/C133 2561 001
MX3IPG2A
2.1 Selecting rated values
The selection of the rated current between 1 or 5 Ampères for
phase protection is made by acting on a jumper that is located
by one of the following points: S20, S21, S22, S23, which can
be reached once the relay has been pulled out (see fig. 1, 4a,
4b, 4c, 4d).
I
WARNING
Dangerous voltages may remain in the device even when the
latter has been de-energized or pulled-out of its casing
(capacitor's memory)
fig. 1
3. OPERATION
3.1 Underresistance protection (rotor ground)
The underresistance protection works by comparing the ratio
between voltage and current injected into the attachment X2/
IPG2A with the set thresholds (R<,R<<): when the calculated
resistance falls below a given threshold,causes the tstart and
the trip timers t1 t2 to trip. If the value remains below the
threshold, once the associated tstart delay is over, the delayed
start command is sent.
If the tripping timers also reach the set overtime, the tripping
command is sent; the partial and total counters related to the
tripped threshold increase their counts and the event logging
session starts.
If a special digital input is enabled which has been set to lock
one or more thresholds, the starting registers are held at zero,
thus preventing operation as long as the input remains ena-
bled.
Threshold R< has a definite time characteristic in the form:
t = t1
3.2 Overcurrent protection (input I)
The device is equipped with an overcurrent threshold (injected
by attachment X2/IPG2A) associated to a tstart and a trip timer.
The overcurrent threshold trip may be locked by feeding a
special digital input purposely set to suit the purpose.
3.3 Undervoltage protection (diagnostics - input U)
The device is equipped with an undervoltage threshold (ap-
plied to attachment X2/IPG2A) associated to a timer. The trip
of the undervoltage threshold can be locked by feeding a
special digital input purposely set to suit the purpose.
3.4 Overvoltage protection (diagnostics - input U)
The device is equipped with an overvoltage threshold (injected
by the attachment X2/IPG2A) associated to a timer. The trip of
the undervoltage threshold can be locked by feeding a special
digital input purposely set to suit the purpose.
3.5 Direct undervoltage protection (input Ucc)
The device is equipped with a direct undervoltage threshold
associated to a tstart and a trip timer. The direct undervoltage
threshold trip can be locked by feeding a special digital input
purposely set to suit the purpose.
3.6 Direct overvoltage protection (input Ucc)
The device is equipped with a direct overvoltage threshold
associated to a tstart and a trip timer. The direct overvoltage
threshold trip can be locked by feeding a special digital input
purposely set to suit the purpose.
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