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A motor represents a balanced three-phase load and, therefore, there is no neutral current, so there is no requirement for a neutral connection. Regulations prevent an earth being used as return, so the star point shouldn't be earthed either.

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How can a dlta connected motor be converted in star?

If the motor terminal has six terminals in the terminal box, then it can be connected either in delta or star. If there are only 3 terminal wires then the motor can not be connected in star.(it means that the motor is designed to be connected in delta only)


What is the difference between a phase to ground connection and a grounded wye connection?

A 'grounded-wye' connection describes a wye-connected supply, whose star-point (or common point) is grounded. This is essential in order to ensure stable phase voltages. I'm not sure what you mean by a 'grounded-phase' connection; if you mean a 'grounded-line' connection, then this is a short-circuit to ground from a line conductor.


What will happen if induction motor is in star-star connected?

If a motor is connected in a star configuration it will operate at a slower speed. This is the working process that a star delta starter operates on. At first through the starter the motor starts in the star connection. When the motor gets up to its highest speed in that connection it times a timer out , the star starter drops out and the delta starter pulls in and then connects the motor in the delta connection. This allows more voltage to be applied to the motor and it then speeds up to its nameplate rated RPM.


What is the time required from changing star to delta?

The change over time will vary with the type of motor, size of motor and the connected load to the motor. The time should be adjusted so that the motor is up to speed and stabilized at the star speed. It is at this point that the change to delta should take place. One thing to note is, do not leave the motor running is the star position any longer that it needs to.


Why zero sequence current cannot flow through a star connected machine unless the neutral is grounded?

If the neutral point is not earthed than the zero sequence current will not have any return path.It will be an open circuit for the zero sequence circuit.

Related Questions

What is the star point of a CT?

The term, 'star point', refers to the common point of connection for the three windings of a star-connected (wye-connected) transformer connection. The star point is usually earthed (grounded) and provides the neutral point of the connection.


How can a dlta connected motor be converted in star?

If the motor terminal has six terminals in the terminal box, then it can be connected either in delta or star. If there are only 3 terminal wires then the motor can not be connected in star.(it means that the motor is designed to be connected in delta only)


What is the difference between a phase to ground connection and a grounded wye connection?

A 'grounded-wye' connection describes a wye-connected supply, whose star-point (or common point) is grounded. This is essential in order to ensure stable phase voltages. I'm not sure what you mean by a 'grounded-phase' connection; if you mean a 'grounded-line' connection, then this is a short-circuit to ground from a line conductor.


Why you are using star connected induction motor and delta connected induction motor?

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What will happen if induction motor is in star-star connected?

If a motor is connected in a star configuration it will operate at a slower speed. This is the working process that a star delta starter operates on. At first through the starter the motor starts in the star connection. When the motor gets up to its highest speed in that connection it times a timer out , the star starter drops out and the delta starter pulls in and then connects the motor in the delta connection. This allows more voltage to be applied to the motor and it then speeds up to its nameplate rated RPM.


How does a star winding shifts to a delta winding in a three phase motor?

To shift from a star winding to a delta winding in a three-phase motor, the connections between the windings need to be rearranged. In a star winding, the ends of the windings are connected to a common point (neutral), while in a delta winding, each winding end is connected to the start of the next winding. By physically switching the connections, the motor can be reconfigured from star to delta winding.


Why use link in star contactor?

The link in the star contactor is used to form the star point of three of the motor leads. On most star wound motors the star point is inside the motor windings. On a motor that can be used for star delta starting it is a six wire motor. The star point winding depends on the contactor to tie the coil ends together externally in the control panel of the star delta starter.


What is the difference of a star or delta connection on motor terminals?

230/400 V These motors can be connected in star to a mains of 400 V between the phases (see figure 1). figure 1 Star connection 400/695 V These motors should be connected in delta to a mains of 400 V between the phases (see figure 2).


How do you know the star delta conection of motor?

The quickest test is, to see if the motor is a six or nine lead motor. In this type of motor the star point is not connected inside the motor but brought out to the motor boxes junction box. A second quick test it to look at the magnetic contactor configuration. There will be a three mag in the setup, two of which will have a tie bar between them. The mags will have the same appearance as reversing magnetics.


What is the time required from changing star to delta?

The change over time will vary with the type of motor, size of motor and the connected load to the motor. The time should be adjusted so that the motor is up to speed and stabilized at the star speed. It is at this point that the change to delta should take place. One thing to note is, do not leave the motor running is the star position any longer that it needs to.


What is the current in star connection?

If a motor is connected in star, the current in the motor winding will be equivalent to the line current. If the motor is connected in delta, the current will be 1/sqrt(3) of the line current. If three phase CTs are connected in Delta, their secondary current will be sqrt(3) higher than the CT ratio implies by the line current.


Why zero sequence current cannot flow through a star connected machine unless the neutral is grounded?

If the neutral point is not earthed than the zero sequence current will not have any return path.It will be an open circuit for the zero sequence circuit.