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EN/04.2021 © STULZ GmbH – all rights reserved
electrical options
11.5.2 Three Phase Control
The phase monitoring relay monitors a phase failure and a phase reversal. Excess voltage, undervoltage and
the phase imbalance are monitored in relation to the set values.
In case of a phase failure the phase monitoring relay is de-energized without delay and triggers an alarm. If the
monitoring relay detects a wrong phase sequence during the A/C unit start, it is not energized and prevents
the unit start.
You can adjust a triggering delay on the relay for the errors excess voltage, undervoltage and phase imbalance
(excess of the adjusted limit values).
Automatic restart
When the defective phase returns and if the voltage is within the limit values and the phase imbalance within
the adjusted tolerance, the A/C unit is restarted automatically.
For this the parameter „Phase restart“ must be set to „1“, in the controller.
When a limit value is exceeded the display lights up in red.
Only when the corresponding restart value is reached
again, the display colour changes to green.
The original display dimensions are 32x16mm.
*The restart value can be set on maximum 3% hysteresis from the triggering value.
Error
Adjustment range
Factory setting
Relay
Excess voltage
(upper limit value)
off, 106-173%
108%
1
Excess voltage
(restart value) *
off, 103-173%
105%
Undervoltage
(lower limit value)
off, 50-94%
92%
Undervoltage
(restart value) *
off, 50-97%
95%
Phase imbalance
off, 4-40%
5%
Phase imbalance
(restart value) *
off, 1-40%
3%
Triggering delay
Relay 1
0,1-20s
3s
Rotating field control 1
5-45°
35°
2
Rotating field control 2
off, L1-L2-L3,
L3-L2-L1, L-L-L
L1-L2-L3
Triggering delay
Relay 2
0,1-20s
0,1s
