Determination Of Transfer Function Of field CONTROLLED DC Servo Motor
PATCHING DIAGRAM TO DETERMINE ARMATURE RESISTANCE Ra
3. To determine field resistance Rf:
- Check whether the MCB is in OFF position in the DC servomotor trainer kit
- Patch the circuit as per the patching diagram
- Put the selection button of the trainer kit in the field control mode.
- The armature terminal is left opened.
- Check the position of the potentiometer; let it initially be in minimum position.
- Switch ON the MCB.
- Vary the pot and apply rated voltage of 220V to the field of the servomotor.
- Note the values of the field current If, field voltage Vf.
- Find the value of field resistance Rf using the above values
If the voltmeter and ammeter in the trainer kit is found not working external meters
of suitable range can be used.
Field Voltage, Va1
Field Current, Ia1
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