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What will happen if the back emf of a D.C. motor vanishes suddenly?
- AThe motor will stop
- BThe motor will continue to run
- CThe armature may burn
- DThe motor will run noisy
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CCommunity
If back emf of a dc motor vanishes suddenly, motor circuit will try to retain back emf by drawing more current from supply.
The voltage equation of dc motor is, Eb = V – IaRa
As the back emf vanishes zero, the whole supply voltage appears across armature and heavy current flows.
If supplying unit didn’t trip down by this time, excess current in armature may heat up the armature and it may cause burning of armature winding.
The voltage equation of dc motor is, Eb = V – IaRa
As the back emf vanishes zero, the whole supply voltage appears across armature and heavy current flows.
If supplying unit didn’t trip down by this time, excess current in armature may heat up the armature and it may cause burning of armature winding.