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What is the voltage measured between a ungrounded star point of a 3ph motor and ground should it be zero?
ChrisBurtle
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What is arcing ground?
Arcing Grounds is a phenomenon which is observed in ungrounded three phase systems. In ungrounded three phase systems operating in a healthy balanced conditions, capacitances are formed between the conductors and ground. The voltage across these capacitances is the phase voltage
Does line to ground voltage always half the value of line to line voltage?
Line to Ground voltage = line to line voltage / 1.73AnswerIt depends what configuration is being measured. In the case of the secondary of a split-phase distribution transformer used to supply residences in North America, the answer is yes. In the case of a star (wye) connected secondary distribution transformer used to supply residences in Europe, no: the line to ground voltage will be as described in the first answer.
What is voltage at a point?
The question is meaningless. Voltage is a measure of electrical pressure, so it must be measured between two points. In many systems, the chassis is used to complete the circuit by providing a return path. In most automotive or truck applications, this is the case. This saves materials cost by needing fewer wires. In those systems, the voltage is measured between ground and the point of interest, but if there is a break in the path along the chassis, the results will be unreliable.
Should there be voltage between ground and each hot of a three phase power system?
There are two types of connections in three phase systems. One is a delta connection where there is no connection to ground, so you should not get any voltage to ground. This is classed as a three phase three wire system. In this type of system any one of the phase wires could become grounded and no one be the wiser. Code requires that grounding lights be added to a delta system to visually show what the phase condition is in relationship to ground. The other type of system is a wye or star point connection. This is classed as a three phase four wire system. In this type of connection the coil ends are all joined together and grounded. You would have voltage between the phases and a lower voltage to ground. The voltage to ground would be the phase voltage divided by 1.73.Yes. If there is no voltage between a hot and a ground, either the hot isn't really a hot or the ground isn't really a ground.AnswerThere is always a potential difference between a line conductor and ground, regardless of whether it is a three-wire system or a four-wire system. This is due to the capacitance between line and ground.
If voltage is zero or very low on one phase and the same as line to line voltage on the other two. Is there a short to ground on the low voltage phase?
From your question it's hard to tell what might be the source of your problem. Is this a primary source to a machine or multiple circuits or from a transformer to just one device like a motor. If it is a short to ground then it should be tripping fuses or breakers if not then you have a unsafe situation in a ungrounded system. If the power is from a transformer then it may have an open winding or blown fuse on either the primary or secondary side.
What is arcing ground?
Arcing Grounds is a phenomenon which is observed in ungrounded three phase systems. In ungrounded three phase systems operating in a healthy balanced conditions, capacitances are formed between the conductors and ground. The voltage across these capacitances is the phase voltage
What are the differences between voltage and potential difference?
Voltage is the potential difference to the ground. By convention, ground potential is zero volt.The above answer is incorrect. 'Voltage', by definition, is potential difference. It has nothing to do with being measured with respect to ground -in fact potential difference (voltage) cannot be measured with respect to anything.
Why doesn't a multimeter read 120 volts between the hot ungrounded conductor and the floor which is the electrical ground?
"ungrounded" = floating.
What are ungrounded conductors and grounded conductors?
Ungrounded conductors, also known as "hot conductors," carry current from the source of power to the load. They are not connected to the ground and usually have a voltage potential. On the other hand, grounded conductors are connected to the ground or neutral point of the power system and are typically used to complete the circuit path and provide a return path for current. They usually have a voltage potential close to zero.
When should you use an ungrounded outlet?
If the wiring system into which you are installing an outlet has no ground available, use an ungrounded outlet. In an ungrounded system, an outlet with a ground contact would allow the outlet user to mistakenly, and perhaps dangerously, assume that a ground was present. A suitable ground may be available as a ground wire accompanying the hot and neutral wires in the cable, or a ground may be available via conductive conduit and a metal outlet box. In any case, use a tester to confirm the integrity of the assumed ground. A voltage test from the hot wire to the ground should show the same voltage as between hot and neutral (the black and white wires respectively). If you are replacing an ungrounded outlet, you need not assume there is no ground present. You may find, in the box, ground wires that were not connected to the outlet. You may come across grounded outlets that have no ground wire attached because they rely on grounding via the mounting screws through the outlet ears to the metal box. This is a less reliable grounding method. It is better to buy a ground-wire "pigtail," fasten the wire directly to a hole in the metal box with the supplied screw, and attach the other end of the ground wire to the outlet via the outlet's ground screw.
How do I rewire an ungrounded plug?
If there is no ground wire connect the ground wire to the neutral wire.
In a 6 pulse bridge rectifier there is an ac voltage when measured between one of the output dc terminal and the ground how do you avoid this ac voltage?
When using a 6 pulse you can't avoid the AC component in your DC voltage. You have to filter it out, use capacitors ! what is the that AC voltage,... It may depend on how the 6 pulse bridge is feed,.. if its feed by a wye transformer and the neutral is grounded, you will see some fraction of that voltage between the DC rails and ground,..
The difference between short to a voltage circuit and short to a ground circuit?
A short circuit is an abnormal connection between two nodes intended to be at different voltages. A voltage circuit is caused intentionally for the purpose of voltage sensing. A ground circuit occurs between a phase and the ground.
How to check for an ungrounded wire?
You can use a wire tester to check for a ungrounded wire. Attached the wire tester to the battery posts. The tester will show you if the ground is weak or strong.
What can happen if a utility-sized electrical generator has an ungrounded neutral?
What you need to define is the statement "utility- sized electrical generator". It depends on what the generators output is used for as to the way it is internally wired. In some configurations there is no neutral to ground as in a Delta configuration.If the generator is configured for a Wye output and the neutral centre tap is not grounded there will be a floating voltage between the generator and the utility system ground. It is for this reason that the generator's neutral point is grounded to bring the floating voltage down to zero volts to ground.
What is it called when wires connect accidentally?
If two ungrounded (hot) conductors touch or an ungrounded and a grounded (neutral) conductor accidentally touch, it is called a short or short circuit. If an ungrounded or a grounded conductor touch an equipment grounding conductor, it is called a ground fault.
What is the voltage between points A and B?
Where EMF is electromotive force, measured in the unit called a Volt, and where 'I' is the electrical current running on a circuit that points A and B are positioned in, and where R is the resistance of that circuit between points A and B, then EMF=I x R, or "Volts" = "Amperes" times "Ohms".
