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How do you do for phase sequence protection at three phase motor operation?
Wiki User
∙ 11y ago
motor is designed to operate in forward and reverse direction for the purpose of elevator. Phase sequence protection is not required.
Wiki User
∙ 11y ago
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How do you turn a 3 phase motor in to a generator?
We can convert a 3 phase ac motor into generator by changing phase sequence of the ac input cable of that motor
What is phase failure relay?
These relay sense the Negative Sequence Voltage components of system supply & offers protection against Phase Failure, Phase Sequence Reversal with Under/Over Voltage conditions which are dangerous to motor winding and cause motor burnouts.
What is the importance of phase sequence?
The importance of phase sequence is related to the direction of rotation for a motor. The three phases set up a rotating magnetic field, which runs the motor. Reverse the sequence, and most motors will run backwards, not necessarily a good thing. There really are only two sequences; ABC, and ACB. All other sequences are permutations of one of these.
What is the symbol of phase sequence?
The symbol of phase sequence is RYB
How do you check phase sequence?
It's outside the scope of this answer to go into the theory, but a 3 phase motor by convention normally rotates anticlockwise when viewed from the 'driven' end. To check phase sequence, the usual method is to use a phase sequence indicator. Originally these were like a miniature three phase motor encased in a hand-held device. If the flying leads were connected RYB, BRY, or YBR, the disc in the psi would rotate anticlockwise. If the flying leads were connected RBY, BYR, or YRB the disc would rotate clockwise. Nowadays, the mechanical aspect of the phase sequence indicator has been repalced with solid state devices that indicate on one of two leds if the sequence is c/w or ac/w. To check phase sequence you look for which phase out of the three phases peaks first. You could probably put each phase on an oscilloscope and see which one peaks first. Phase sequence is usually taken as positive anticlockwise from the reference voltage ( the phase that peaks the first).
Will a 3 phase motor work on grounded B phase?
If the motor is connected to an ungrounded delta supply service there will be no effect on the operation of the motor. If the motor is connected to a wye system supply service and the B phase grounds out, the motor's overload protection would take the motor off line from the electrical supply.
Why to knw phase sequence?
If you reinstall a three-phase motor with two of the supply conductors interchanged, then the resulting negative phase sequence will cause the motor to run in reverse.
How do you turn a 3 phase motor in to a generator?
We can convert a 3 phase ac motor into generator by changing phase sequence of the ac input cable of that motor
What is phase failure relay?
These relay sense the Negative Sequence Voltage components of system supply & offers protection against Phase Failure, Phase Sequence Reversal with Under/Over Voltage conditions which are dangerous to motor winding and cause motor burnouts.
What is the difference between positive sequence and negative sequence arrangement?
The order in which the voltage of the coil reaches to the maximum value is called the Phase Sequence.POSITIVE PHASE SEQUENCE: If the coil is rotated in anticlockwise direction, the phase sequence will be Positive Phase Sequence, i.e., R-Y-B or A-B-C.NEGATIVE PHASE SEQUENCE: If the coil is rotated in clockwise direction, the phase sequence is called Negative Phase Sequence, i.e., R-B-Y or A-C-B.NOTE: Phase Sequence is of great importance in parallel operation of three phase transformers and alternators.
What is the importance of phase sequence?
The importance of phase sequence is related to the direction of rotation for a motor. The three phases set up a rotating magnetic field, which runs the motor. Reverse the sequence, and most motors will run backwards, not necessarily a good thing. There really are only two sequences; ABC, and ACB. All other sequences are permutations of one of these.
Will 3 phase AC motor stay running if you remove 1 phase?
Yes but it will not start. Usually if you lose one phase the current will go higher on the other phases and the motor overload protection will disconnect the motor from the supply voltage.
How is it possible that a chicken rotisserie that uses 208v 3 phase can have a motor that uses 208v?
Two scenarios are that the motor could be a three phase motor. These three phase motors are manufactured in smaller sizes. The other scenario is that the motor is a 208/220 volt single phase motor. It will operate on 208 volts by taking two legs of the three phase supply for its operation.
What is negative phase current?
Negative Phase Sequence is Phenomena generally found in motors,the formula for positive phase sequence is : Ip= Ir + a * Iy + a^2*Ibthe formula for negative phase sequence is : In= Ir + a ^2* Iy + a*IbAs the name suggest the sequence of current or the mmf is in reverse order, a reverse order current in stator will produce a reverse order mmf, now this reverse order mmf is rotating in direction opposite to the rotor of the motor, thus the mmf cut is very high and so current induced in stator is considerably high; as for normal mmf it is in direction of rotor so mmf cut is very small thus current induced is very small.this high current in your rotor leads to overheating of your motor and finally burning of your windings.CommentNegative phase sequence is not 'generally found in motors'. But one of the effects of negative phase sequence would be to cause a three-phase motor to reverse direction.
What is the functional operation of a single-phase capacitor start motor?
As with any motor the function is to turn electrical energy into mechanical energy.
What is the symbol of phase sequence?
The symbol of phase sequence is RYB
How do you check phase sequence?
It's outside the scope of this answer to go into the theory, but a 3 phase motor by convention normally rotates anticlockwise when viewed from the 'driven' end. To check phase sequence, the usual method is to use a phase sequence indicator. Originally these were like a miniature three phase motor encased in a hand-held device. If the flying leads were connected RYB, BRY, or YBR, the disc in the psi would rotate anticlockwise. If the flying leads were connected RBY, BYR, or YRB the disc would rotate clockwise. Nowadays, the mechanical aspect of the phase sequence indicator has been repalced with solid state devices that indicate on one of two leds if the sequence is c/w or ac/w. To check phase sequence you look for which phase out of the three phases peaks first. You could probably put each phase on an oscilloscope and see which one peaks first. Phase sequence is usually taken as positive anticlockwise from the reference voltage ( the phase that peaks the first).
