ABB Relion 611 Series, Technical Manual

Page: 144 / 536

When the motor is started, a separate function is used for the startup protection, and
JAMPTOC is normally blocked during the startup period. When the motor has passed
the starting phase, JAMPTOC monitors the magnitude of phase currents. The function
starts when the measured current exceeds the breakdown torque level, that is, above
the set limit. The operation characteristic is definite time.
The function contains a blocking functionality. It is possible to block the function
outputs.
4.1.4.4 Operation principle
The function can be enabled and disabled with the Operation setting. The
corresponding parameter values are "On" and "Off".
The operation of JAMPTOC can be described with a module diagram. All the modules
in the diagram are explained in the next sections.
GUID-93025A7F-12BE-4ACD-8BD3-C144CB73F65A V2 EN
Figure 62: Functional module diagram
Level detector
The measured phase currents are compared to the set Start value . The TRMS values
of the phase currents are considered for the level detection. The timer module is
enabled if at least two of the measured phase currents exceed the set
Start value .
Timer
Once activated, the internal
START
signal is activated. The value is available only
through the Monitored data view. The time characteristic is according to DT. When
the operation timer has reached the
Operate delay time value, the
OPERATE
output is
activated.
When the timer has elapsed but the motor stall condition still exists, the
OPERATE
output remains active until the phase currents values drop below the Start value , that
is, until the stall condition persists. If the drop-off situation occurs while the operating
time is still counting, the reset timer is activated. If the drop-off time exceeds the set
Reset delay time , the operating timer is reset.
The timer calculates the start duration value START_DUR, which indicates the
percentage ratio of the start situation and the set operating time. The value is available
in the monitored data view.
Section 4
1MRS757454 D
Protection functions
138 611 series
Technical Manual