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For a balanced three-phase load, the neutral current is zero, so the loss of the neutral would have no effect.

However, for an unbalanced load, the 'difference' between the line currents results in a neutral current.

So, for an unbalanced load, if no neutral current can flow, then the load's neutral point will no longer remain symmetrical, and the line voltages will become unbalanced. If the unbalance is severe, then individual loads may be subject to over-voltages or under-voltages.

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12y ago
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11y ago

The neutral carries away all the unbalanced circulating current in the unbalanced network. SO, if disconnected, some lines will be oveloaded and thus the circuit breaker will trip.

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The simple answer is that the loads' phase voltages will become unbalanced. That is, the voltage across each phase will no longer be 1.732 x line voltage.

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12y ago

There is no neutral in a three phase circuit

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Q: What happens if neutral of three phase four wire system is break?
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Related questions

What is break load?

TPN Load break switch: Is basically a main switch used in three phase system and know as Three pole neutral or Three phase neutral having four connectors for three phases and one neutral.


What is the code ruling in the US on 3 phase branch circuits and the neutral?

A three phase system will have 3 phase branch circuits and no neutral.


Why the neutral cable takes high current than the phase lines in three phase installation?

In a properly balanced three phase system, there is negligible current on neutral. If there is substantial current on neutral, then the system is not balanced and/or something is wrong.


What is a tpn switch?

TPN stands for Triple Pole With a neutral link.normally this are the switches which are used in case of three phase connections and as main switch......gonecase17@gmail.com


Condition of three phase in which there is no need of neutral?

A delta-connected system is described as being a three-phase, three-wire, system, and doesn't have a neutral. But a balanced star (wye) connected load (e.g. a three-phase induction motor) doesn't actually require a neutral.


Why neutral cross section is half the phase in three phase cable while it has to carry current of summation of all phase..?

The current carried by the neutral of a three phase four wire system is the un balanced current. If the three phase system was completely balanced on all three phases there would be no need for a neutral, eg a three phase motor. This neutral current will be less that the phase current so a reduction in the neutral size is allowed.


What is the difference between neutral point and earthing?

Earthing point is where conductor is directly connected to ground and its potential is always zero. Neutral is a return path in single phase system and in three phase system Neutral point will have zero potential if all the loads are balanced in the system. In un balanced three phase system even neutral point will have some potential


What is line phase neutral?

Line, phase, neutral are terms used to describe the conductors in a three-phase system. The three live wires are called 'lines', and less correctly, 'phases'. Neutral is used for the fourth wire which in a balanced system carries no current.


What would be the effect on the neutral bar of a 3 phase D B if the main incoming neutral is lost?

A three phase delta system does not use a neutral in its operation.


What is the limit or range of the neutral current in an unbalanced three phase system for it to be regarded as faulty?

The limit or range of the neutral current in an unbalanced three phase system is the third harmonic in single phase non-linear load current is the major contributor to neutral current.


Can the neutral conductor be downsized in a 3 phase electrical system?

Yes, you can reduce the neutral in a three phase system. you must figure the unbalanced current the neutral will carry and also make allowances for any harmonics that may be present.


Why neutral is not requied in 3 phase?

As far as I understand, you don't need neutral line for connecting appliances that is 3-phase compilant. You only need the neutral line to connect a single phase appliance, which you connect along with one of the three lines.