Operating Principle - ABB CM-MPN Instructions D'installation

Threshold values for phase unbalance
Switch-off value:
L1-L2-L3: 2-25 % (unbalance value in percentage)
Unbalance value in percentage =
(max. difference L1,L2,L3 / average value L1,L2,L3) x 100 %
Switch-on value:
Set switch-off value -20%

Operating principle

Over- and undervoltage, 1 x 2 c/o contacts
If all three phases are present with correct voltage, the output
relays are energized. If the voltage to be monitored exceeds
or falls below the set threshold value, the output relays de-
energize instantaneously or delayed (0.1-30 s), depending on
the set time delay. The fault type is indicated by LEDs. The
output relays re-energize automatically, instantaneously or with
delay (0.1-30 s), depending on the set time delay, as soon as the
voltage returns to the tolerance range, taking into account a
fixed hysteresis of 5 %.
Over- and undervoltage, 2 x 1 c/o contact
If all three phases are present with correct voltage, the
output relays are energized. If the voltage to be monitored
exceeds the set threshold value, output relay R1 de-energizes
instantaneously or delayed (0.1-30 s), depending on the set
time delay. If the voltage to be monitored falls below the set
threshold value, output relay R2 de-energizes instantaneously
or delayed (0.1-30 s), depending on the set time delay. The
fault type is indicated by LEDs. The output relays re-energize
automatically, instantaneously or with delay (0.1-30 s),
depending on the set time delay, as soon as the voltage returns
to the tolerance range, taking into account a fixed hysteresis
of 5 %.
Phase unbalance
If all three phases are present with correct voltage, the output
relays are energized. If the phase unbalance of the phases to be
monitored exceeds the set unbalance threshold value, the
output relays de-energize instantaneously or delayed (0.1-30 s),
depending on the set time delay. The fault type is indicated by
LEDs. The output relays re-energize, instantaneously or with
delay (0.1-30 s), depending on the set time delay, as soon as the
voltage returns to the tolerance range, taking into account a
fixed hysteresis of 20 %.
Phase sequence and phase failure
If all three phases are present with correct phase sequence, the
output relays are energized. They de-energize immediately if a
phase failure or a phase sequence error occurs. The fault type is
indicated by LEDs. The output relays re-energize automatically
as soon as the voltage returns to the tolerance range.
Automatic phase sequence correction
Applying control supply voltage / three-phase measured
voltage with correct phase sequence, energizes output relay R2
when the fixed start-up delay t
Relay R2 remains de-energized if the phase sequence is
incorrect.
If all three phases are present with correct voltage, output relay
R1 energizes when the fixed start-up delay t
complete. If the voltage to be monitored exceeds or falls below
the set threshold values for phase unbalance, over- or
undervoltage or if a phase failure occurs, output relay R1 de-
energizes.
Output relay R2 is responsive only to a false phase sequence. In
conjunction with a reversing contactor combination, this
enables an automatic correction of the rotation direction (see
circuit diagram on page 5).
of about 200 ms is complete.
s2
of about 250 ms is
s1
The operating mode
correction' can be selected only when ‚Phase sequence
monitoring activated' (DIP2: OFF) and ‚2 x 1 c/o contact'
(DIP3: ON) is selected.
With the operating mode ‚Automatic phase sequence
correction', the phase sequence error has the lowest error
priority for the status indication.
CM-MPS.11, CM-MPS.21, CM-MPS.23:
Interrupted neutral monitoring
The interruption of the neutral in the main to be monitored is
detected by means of phase unbalance evaluation. Determined
by the system, in case of unloaded neutral, i.e. symmetrical load
between all three phases, it may happen that an interruption of
the neutral will not be detected.
Displacement of the star point by asymmetrical load in the
three-phase main. Interrupted neutral will be detected.
‚Automatic phase sequence
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