ABB RELION REX640 Technical Manual page 1344

Supervision functions
in PCM600. Similarly, the TEMP_RL output of MPTTR must be connected to the
TEMP_RL input of this function in Application Configuration in PCM600.
When the emergency start signal START_EMERG is set high and if the value of the
cold or warm counter is above its start value setting, the value of the counter is
set one count less than the respective maximum number of start value setting. This
disables BLK_RESTART and OPERATE which makes the restart of motor possible.
The values can be reset by activating the RESET binary input. The activation of the
RESET input also resets the counter decrease timer. The counter value can also be
reset on the Clear menu.
Limit supervision
This module compares the motor cold and warm count to the set
start and Max Num warm start , respectively. The BLK_RESTART output is activated
when either the cold or the warm start counter reaches the set
Max Num warm start , respectively. The OPERATE output is activated when either
or
the cold or the warm start counter exceeds the set
warm start , respectively.
When the BLK_RESTART output is active, T_RST_ENA shows the possible time for
the next restart. The value of T_RST_ENA is calculated as the time left for both
counters to decrease below their maximum number of starts.
Activation of the BLOCK input blocks both OPERATE and BLK_RESTART outputs.
6.7.5 Application
Repeated motor starts increase the temperature to a high value in the stator or
rotor windings, or both, unless enough time is allowed for the heat to dissipate.
To ensure a safe operation, it is necessary to provide a fixed-time interval between
starts or limit the number of starts within a period of time. This is why the motor
manufacturers have restrictions on how many starts are allowed in a defined time
interval.
This function counts the number of cold and warm starts and provides a block
restart signal when the number of starts reaches the permitted limit. The customer
can use this signal for blocking a new start operation. An operate signal is also
available which can be used to disconnect the motor when the number of starts
exceeds the limit.
6.7.6 Signals
1344
1MRS759142 F
Max Num cold
Max Num cold start
Max Num cold start or Max Num
Technical Manual
REX640