A starting resistance is inserted at the starting in an induction motor as well as dc motor.
Considering a human handed control system for the dc motor speed control, if the resistance wire cut out too slowly, then
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A 100 hp, 250 V, 350 A shunt dc motor with an armature resistance of 0.05 ohms. To limit maximum starting current to twice the rated of its value, what will be the number of stages of starting resistances?
Following are the observations due to large starting current in dc motor.
(i) Sparking at brushes
(ii) Mechanical shock at shaft
(iii) Source current fluctuations
(iv) Burning of the field winding
The direct-on-line starter is used to start a small dc motor because it limits initial current drawn by armature circuit.
Thyristor controlled starter is preferred over DOL starter due to
For a 7.46 kW, 200 V dc shunt motor with full load efficiency of 85% has armature resistance of 0.25 ohms. Calculate the value of starting resistance in ohms for a current 1.5 times of the full load current.
19 videos|90 docs|25 tests
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19 videos|90 docs|25 tests
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