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The secondary side (output) of a three phase transformer develops a "separately derived system". That is why you do notsupply a neutral to a three phase transformer. It develops its own reference to ground by being bonded to the transformer casing and to a substantial earth ground, such as a ground rod. The XO tap on a transformer provides the neutral to the secondary line. It will have a double wire lug. The neutral wire going to the panel being supplied goes under one lug and the same size wire is to go to the ground lug on the transformer chassis The ground lug is also a double with the other lug to be wired to the earth ground.

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Q: Why is the neutral point grounded on a transformer?
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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.


What happen if you apply triangular input to transformer?

there will be no neutral point in the circuit and high voltage will be across the transformer coils


What does floating neutral mean on a generator?

It means the neutral is not grounded.


What is the reason why the neutral is not used on high resistance grounding?

The question doesn't provide enough detail to give a definitive answer. The neutral PD is often used in protective functions on high resistance grounded generators (when grounded through a transformer). High resistance grounding limits the use of transformers - you must be using balanced loads, since very little current will flow (typically around 5-20amperes max) to the neutral. Because of this, phase to neutral values (such as voltage) are meaningless. Any current flowing in the neutral will cause an offset in all three phases from neutral. Since the neutral is high resistance grounded, it does not take a significant amount of current to cause significant offset.


Why no electric shock from neutral line?

There is normally no voltage on the neutral line because the neutral line is grounded. However, and this is always important, do not assume that neutral is grounded, nor that there is not an elevated voltage on neutral or ground due to a possible ground fault.

Related questions

How do the earth active and neutral wires work in a house?

Neutral mean is zero potential and neutral wire it has been taken from the Distribution Transformer " Y " point (Xo). This point " Xo " is directly grounded through the dedicated grounding system.


Voltage across Neutral and earth for a 3 phase auto transformer?

A grounded neutral will be at earth potential. A floating neutral will be at a voltage dependent upon the voltage imbalance between phases, and the design of the transformer.


Why neutral is ground in the circuit?

In the transformer at the secondry side one end of the winding will make star connection means 0 point there will be no voltage at that end if any leake voltage appear at that point it have to ground that what all the neutral points to be grounded


Why would you get 65volt on 120volt output on a 480volt to 120volt transformer?

Your neutral May not be grounded good


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.


Can you applied the voltage to neutral of the transformer?

The neutral of a transformer is usually grounded. Under this situation, this question is the same as asking whether you can apply a voltage to ground; the answer is yes, but I don't know why you'd want to. Sometimes transformer neutrals are insulated away from ground. If this is done, then you could inject "backwards" from the neutral up into the transformer. Again, I don't know why you would want to do this, though.


Do all electrical power sources flow to earth e.g. Secondary winding of an isolating transformer with no earth connection on the neutral line?

There are situations where the secondary of a transformer is not grounded and the neutral is not connected to the neutral of the primary. This can cause a potential shock hazard so the secondary side needs to be protected.


What happen if you apply triangular input to transformer?

there will be no neutral point in the circuit and high voltage will be across the transformer coils


What is the reason for using a neutral current transformer on a transformer?

A current transformer is primarily used at the neutral point of a transformer for earth fault protection. A neutral current transformer will measure any ground fault current which will essentially flow from the star point of the transformer. A fault-detection device other devices is connected to the current transformer and, if the fault current exceeds a certain trigger value, the fault-detection device will give a trip command to an earth-fault relay to disconnect the supply of electricity to the transformer.


What is role of neutral in three phase system?

In a three phase system, connected wye, neutral is the common return, and it is grounded. In a delta connection, there is no neutral.


Why is one terminal of a three-phase AC generator grounded?

only neutral point is gronded not a terminal ,


Does a 3 phase motor starter with a 120 volt coil need a neutral to the coil?

Usually for this type of installation there is a control transformer installed in the starter enclosure. The primary of the transformer is the motors line voltage and the secondary is the control voltage which is usually 120 volts. In Canada the control transformer needs fusing on the secondary side of the transformer. In the US the transformer needs fusing on the primary and secondary sides of the transformer. The secondary side of the transformer's terminals are labeled X1 and X2. The X2 lead is grounded to the starter's enclosure. From this point out the wire is then termed the circuit's neutral wire. This wire then connects to one side of the magnetic starters draw in coil. Yes, 120 volt coil would require a neutral, this could be derived from the control transformer if it has one or from an external source.