Woodward MRM4, Руководство пользователя

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Protective Elements
Testing pick-up threshold
The drop-out delay time should be 0s for this test.
Feed in a testing current significantly lower than the threshold of the mechanical load shedding. The test
current has to be increased until the relay is energized. When comparing the measured values with those
of the ammeter, the deviation must be within the permissible tolerances.
Testing drop-out threshold
For testing the drop-out threshold the testing current has to be significantly greater than the pick-up
threshold value. The test current has to be decreased until the relay is falls back. When comparing the
measured values with those of the ammeter, the deviation must be within the permissible tolerances.
Testing the delay times
This test is only possible, if the motor is in run mode.
Testing the trip delay
For testing the pick-up delay , a timer is to be connected to the contact of the associated trip relay. Feed
in a testing current significantly lower than the pick-up value, the test current has to be increased suddenly
above the threshold. The timer is started when the limiting value of the tripping current exceeded the
threshold and it is stopped when the relay trips and the operating time is elapsed .
Testing the drop-out delay
For testing the drop-out threshold, the testing current has to be significantly greater than the pick-up
threshold. A timer is to be connected to the contact of the associated trip relay. The test current has to be
decreased suddenly below the drop-out threshold. The timer has to be started when the limiting value of
the tripping current falls below the threshold and it has to be stopped when the relay falls back.
Successful test result
The measured tripping delays and threshold values comply with those values, specified in the adjustment list.
Permissible deviations/tolerances can be found under Technical data.
RTD - Temperature Protection [23]
Elements:
RTD
General – Principle Use
The Resistance-based Temperature Detector (RTD) protection module uses temperature data that are provided
by a Universal Resistance-based Temperature Detector (URTD) module (please refer to the URTD Module
section).
The protective device provides tripping and alarming functions based on the direct temperature measurements
read from the URTD device that has 11 temperature sensor channels. Each channel will have one trip function
without an intended delay and one alarm function with a delay.
The “trip” function has only a threshold setting. The trip threshold is usually set close to the thermal capacity. As
soon as the thermal capacity used reaches the trip threshold, the Device will trip with no delay.
Each individual »Alarm Function« has a threshold setting range and can be individually enabled or disabled. It
also has a timeout delay. The timeout flag will be set when the thermal capacity used has been above the alarm
threshold for the timeout delay. The alarm threshold can be set much lower than the trip threshold. Therefore,
when the thermal capacity used reaches the alarm level, it will not impose immediate danger to the electrical
equipment. Both the alarm (pickup) and timeout alarm flags are part of the products Relay Output assignment
list, so it is the user’s choice to use alarm pickup or timeout for their applications. The dropout ratio for both trip
and alarm is 0.99.
Besides each individual RTD protection/alarm function, there are also group RTD protection/alarm functions.
These RTD groups behave very much like the individual RTD functions described above, but they have
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