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Activation and parameterization | 4
If the relay is deactivated, then the semiconductor conducts the current during
the entire on-time of the motor and this leads to overheating of the motor starter
depending on the motor size. Internal temperature monitoring leads to the motor
shutting off as soon as the maximum module temperature permitted has been
reached.
Bit F: „1" = reserved
4.2.3.4 Measuring constant (parameter 0x0025)
The measuring constant is the time, after the motor has been switched on, that current
symmetry and downtime current is monitored after stop.
The preset value is 2000 ms (7D0hex).
This monitoring enables the direction relay to be deactivated if the current would flow in
error while in a deactivated state. A message is generated as well if e.g. a current path can
no longer be deactivated.
Application example
If a motor is only started for a short time and immediately switched off, then this time
constant must be increased, so that the device is not shifted into a state of error and restart
is disabled.
4.2.3.5 Deactivation constant (parameter 0x0026)
The factor for overload protection is necessary for calculating the I2t –characteristic and
the maximum current. The tripping time of safety equipment is to have an effect in
accordance to diagrams about the parameter "deactivation constant."
Depending on the size of the value, the trip characteristic and motor protection
responsiveness is optimized depending on motor size and load characteristics.
24
NOTE
Wieland Electric GmbH | BA000628 (Rev.A) | 04/2009
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