Operation Principle - ABB RELION REX640 Technical Manual

Section 6
Supervision functions
6.7.4
1238
TEMP_RL calculated by the thermal overload protection is used to distinguish
between a cold and warm start.
The function contains a blocking functionality. It is possible to block the function
outputs or the function itself.

Operation principle

The function can be enabled and disabled with the Operation setting. The
corresponding parameter values are "on" and "off".
The operation of MSCPMRI can be described with a module diagram. All the modules
in the diagram are explained in the next sections.
MOT_RUN
TEMP_RL
Motor start
counter
RESET
START_EMERG
BLOCK
GUID-4187B933-0975-4E60-B129-A7436BEB3C46 V1 EN
Figure 674: Functional module diagram
Motor start counter
This module counts the number of motor starts. The value of the cold count
COLD_COUNT and warm count WARM_COUNT is available in the Monitored data
view. On the rising edge of MOT_RUN, the module increments the cold start counter.
If the thermal content available at the TEMP_RL input is above the set Warm start level
when the rising edge of the MOT_RUN input is received, both cold and warm start
counter values are incremented.
If Operation of the thermal overload protection for motors function
MPTTR is set as "Off", the TEMP_RL value is not available. In this
case, the warm start counter does not increase.
The counter decrease timer also starts at the first increment of the cold start counter
(that is the first time when the counter increases from zero). When Cnt decrease time
elapses, both cold and warm start counters decrease by one and the counter decrease
timer restarts. This is repeated until both cold and warm counters are zero.
When the motor is not in operation, that is, the motor is in stop condition, it takes more
time to cool. During such condition Cnt decrease time is multiplied by a Cnt Dec timer
Mult setting.
The motor start detection is available at the MOT_START output of the motor start-up
supervision function STTPMSU. The MOT_START output of STTPMSU must be
connected to the MOT_RUN input of this function in Application Configuration in
OPERATE
Limit
supervision
BLK_RESTART
1MRS759142 C
REX640
Technical Manual