Manual MRM3-2 GB
Woodward
TD_MRM3-2_09.08_GB_Rev.New
27
5.5 Start
Supervision
The MRM3-2 can offer two start supervision methods:
•
Automatically by means of the thermal load
•
By a limited number of starts per time interval
5.5.1 Duration of a Start Cycle (No.+Start)
AUTO
If this mode is selected, a start is always possible if sufficient start reserves are available according
to the thermal image. This function operates dynamically on the data of the previous starts (see
chapter 4.1.1).
Time Adjustment
By this the interval of the permissible number of starts is timed.
The number is defined in the next parameter.
EXIT
The element is deenergised.
5.5.2 Number of Starts per Cycle (No.+Start)
This parameter is only visible if a time was selected with the preceding parameter which defines
the number of permissible starts during the respective interval.
5.5.3 Start Blocking Time (Start+Block+t>)
This parameter is only visible if a time was selected (chapter 5.5.1). It defines the time for a new
start when the number of starts per interval was exceeded. The following is possible:
VARI
A new start is possible after the remaining time of the interval has run down.
Time Adjustment (s):
Restarts are blocked for the adjusted time.
5.5.4 Characteristic for the Starting Time
In some motor applications it may happen that the supply voltage is lower than the rated value.
Lower rated values have lower starting currents and consequently longer starting times. The start-
ing time can be extended by selecting a characteristic. The setting "DEFT" means that a maximum
starting time is fixed. The subsequent parameter "Rated starting current" is not active. The setting
"INVS" means that the maximum starting time is variable. It is determined by the rated starting cur-
rent and the permissible starting time at rated voltage (refer to Chapter 7.4.1).
5.5.5 Rated starting current I_Start
The basis for calculating the maximum starting time is the rated starting current I_Start of the motor
at rated voltage.
