What happen if LV supply is fed to a HT motor?
Answer Posted / anand ahuja
If 415V 3-ph 50Hz power supply is connected to a motor which
is rated, say, 3.3kV or 6.6kV or 11kV, the motor will not
start at all as it will not develop sufficient magnetic
field and there it will not develop sufficient torque.
Basically, the number of turns in a HT motor are high
compared to the no. of turns in an LT motor. When LT
voltage is applied to HT motor, the voltage drop per turn or
the emf per turn is very low and thereby it does not develop
sufficient magnetic field.
In case of a star-delta start of normal LT induction motor,
the voltage applied (or potential applied) to the windings
is less in star connection than that in delta connection.
In case of LT motors, the current drawn is high on low
voltage being applied to it when it is within a certain
range. That is a 415V motor is connected to 380V or 320V
supply.
Whereas, applying 415V to a 3,300V or 6,600V or 11,000V
motor is similar to applying voltage as low as 20V to 40V to
415V motor.
| Is This Answer Correct ? | 31 Yes | 8 No |
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