9 Visualization
Maschinenfabrik Reinhausen GmbH 2020 3076385142/08 EN ETOS
®
ED
▪ Large tap change: Tap selector operation in which the distance between
the attached selector contacts used for this tap-change operation is large.
▪ Reverse tap-change operation: Tap-change operation in which the tap
changes in the opposite direction to the most recent tap-change operation
and does not involve actuation of the selector.
9.32.3 Limit values
The monitoring system monitors the tap-change sequence for the following
limits:
▪ Limit value > (M1...M8 >)
▪ Limit value >> (M1...M8 >>)
▪ Maximum permissible torque of the on-load tap-changer (M
d,max
)
Limit value > and limit value >>
2 limit values (> and >>) are defined for each tap-change range (windows
M1...M8). These limit values depend on the tap changer, type of tap-change
operation, and the diverter switch and transformer oil temperatures currently
measured.
Once the tap-change operation is complete, the monitoring system checks
the torque curve for the defined limit values. If the limit value was exceeded,
the monitoring system generates a corresponding event message. If the limit
value >> is exceeded, additional tap-change operations are blocked based
on the device configuration. In this case, the Blocking active event is trig-
gered. You must acknowledge events to ensure they are no longer displayed
and to disable the associated blocking function.
Maximum permissible torque of the on-load tap-changer (M
d,max
)
During the tap-change operation, the maximum permissible on-load tap-
changer torque is monitored. This prevents physical damage to the on-load
tap-changer. If the limit value for the maximum permissible on-load tap-
changer torque is exceeded, the monitoring system triggers the motor pro-
tective switch Q1. Additionally, the monitoring system triggers the event Max.
motor torque limit value exceeded. During a change-over selector operation,
the Q1 motor protective switch is not triggered in windows M3...M5.
As soon as the motor protective switch is triggered, the monitoring system
receives a signal to this effect from the motor-drive unit. The monitoring sys-
tem then triggers the event 85 Motor protective switch is triggered!.
You cannot insert the motor protective switch again until the event Max. mo-
tor torque limit value exceeded has been acknowledged. Follow the operat-
ing instructions for fault elimination in the motor-drive unit operating instruc-
tions.
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