Initially motor starts with star connection ,after few
timing changes to delta connection, why the motor should
run continously in star connection,it gives high torque &
low current?
Answers were Sorted based on User's Feedback
Answer / madhu
basically in star connection line current is equal to phase
current,it gives high starting torque. after motor reaches
pick up speed we changed to delta.because in delta line
voltage is equal to phase voltage& line current is root 3
times the phase current.if we run in star in running time
the power losses are more due to current is high. thats why
we changed star to delta.
Is This Answer Correct ? | 18 Yes | 3 No |
The purpose of starter is to start the motor and to limit
the starting current.we are starting the motor in y-
connetion during this impedence of two windings put across
the line voltage hence the starting current gettinh
redeuced
but the motor rated capacity (out put torque)can only be
obtained when itis changed to delta connection this time
the voltage is incresed bu 1.732 time to meet the torque
(torque is direct proportion to square of supply voltage .
Is This Answer Correct ? | 7 Yes | 1 No |
Answer / velusamy
There are two reasons
1.To get high starting torque, motor runs at star for
predetermined duration and then changed to delta.
2.If the motor runs continuously , the capacity of the
motor is reduced by root 3 times (Capacity of motor
rating/1.7324) and hence motor will fail if the OL setting
is not reduced to 1.7324times of motor full load current).
Is This Answer Correct ? | 6 Yes | 2 No |
if we keep frequency constant can we cal a synchronous generator as a dc generator
A power transformer 4MVA/11KV/0.415Kv has been out of use in 12years. what maintenance actions/test need to be carried out before energizing.
In Indian Railways , how the AC motor is driven? Please explain clearly starting from the overhead 25kV supply.
What are the types of windings present in the ceiling fan? What winding will be effective first when we started the fan?What are the resistance and inductance ratios comparatively at the initial speed and full speed of the fan?
what is the difference between c power and U power acb breaker
hopkinson's test
How shall i select the value of capacitor or inductor in a system?
Why does a TV set have two pin plug whereas the moniter of a computer has three pin plug? Isn't the earthing protection required for the TV set
Why ground terminal is used in pot meter 10k ohms
could anybody able 2 send me jindal steels previous papers fr electrical steam....pls send 2 my id if possible....sirisha.shaik@gmail.com
please give me all the Alarm .Trip ,Safety Relays & Conditions of Chiller mail me on ashokbabunhce@gmail.com
why dont we use the same pylon to carry 400 kv plus 220kv and 33 kv ?
2 Answers Focus, Focus Energy,