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Why is it not good to operate a transformer above its nominal voltage?
Wiki User
∙ 14y ago
Operation above the rated supply voltage causes the ferromagnetic core to enter saturation; this means that the primary inductance is reduced and since the primary current is limited by primary resistance +inductance then the primary current will increase and possibly cause the primary winding current capacity to be exceeded. Also the iron core hysteresis loss will likely increase and cause the core temperature to rise. We have not considered eddy currents in the core, probably these are less than the hysteresis core loss.
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Addition:
also the stresses that caused by increasing the voltage will over heat the transformer by mean the life time is redused, for example: if the life time for a transformer is 20 years this number will decrease due to operating the transformer on a higher voltages than the rated...
Wiki User
∙ 14y ago
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What is the capacitive voltage transformer in sub station?
A coupling capacitor voltage transformer (CCVT) is composed of two stacks of capacitors which step the primary voltage down to a lower voltage potential transformer. These are typically used on 100kV and above, and the potential transformer is often around 15kV on the primary side. There are two reasons to use CCVTs over PTs (potential transformers) - at the above voltage levels, they are cheaper, and they can be used for power line carrier signal injection. Under transient conditions, CCVTs typically won't perform as well as PTs, and also may have worse accuracy ratings, so are often not acceptable for metering purposes.
What is the difference between a step up transformer and a step down transformer?
the main function of transformer is to change the magnitude of Voltage. difference between step up and step down is step up will change the input voltage into a larger magnitude of output while step down is vice versa
When a larger voltage is applied to a conductor does the current increase or decrease?
If you increase the voltage applied to a conductor, the current increases.That is, unless you are talking about stepping up the voltage with a transformer with the intent of distributing it over a long distance to a remote transformer, at which point you would step it back down. In this case, the current would decrease. The above answer to the original question remains valid, however, due to lack of information.
What is the role of magnetizing current in transformer?
connect 3 - phase supply to transformer primary winding.....keep transformer secondary winding open..... apply 3-phase voltage i.e.400v ac, and measure the amount of current flowing in each phase of the transformer primary winding...this current is the transformer magnetising current..... we can keep multimeters in series with the source....so we can measure directly the current readings.....(keep multimeters in current mode, and generally magnetising current will come in terms of milli amps for 400 v )
What is a phase shifting transformer?
This applies to three-phase transformer connections. 'Phase shift' or 'angular displacement', is defined as 'the angle by which the secondary line-to-line voltage lags the primary line-to-line voltage'.Angular displacement depends on the type of transformer connection. The most common are:delta/delta results in an angular displacement of 0o or 180owye/wye results in an angular displacement of 0o or 180odelta/wye results in an angular displacement of 30o or 210owye/delta results in an angular displacement of 0o or 180oThe angular displacement for all possible combinations of three-phase transformer connections are listed in transformer vector group charts.Angular displacement determines whether or not it would be possible to parallel different types of three-phase transformer connections. For example, from the above data, it would be impossible to parallel, for example, a delta/delta transformer with a delta/wye transformer.
What is nominal zener voltage?
A zener diode has a voltage when it reachesbreak over it may be 5v 12vor other voltage as manufactured. The manufacture will produce a 5v zener or is it? This voltage can change from device to device but the mean or nominal voltage will be as close as 5v as possible. So when buying a 5v zener do not expect 5v absolute but a nominal 5 v ZENERS are designed for a specific voltage [ THEREFORE NOMINAL] as mentioned above . depends on the voltage required it can be bought within a specific voltage -/+ a % of the breakdown
What is meant by a nominal current?
The word nominal means the lowest possible safe amount. So, nominal current or nominal voltage is the lowest amount necessary to perform an electrical function like keeping a light turned on.AnswerThe original answer is incorrect. 'Nominal' simply means 'named'. So a 'nominal voltage' is the 'named voltage', as opposed to an 'actual voltage'. For example, the nominal voltage of residential supplies in the UK is 230 V; however, this value is allowed to vary between +10/-6% of the nominal voltage. In other words, a nominal voltage of 230 V may vary between 216 V and 253 V.
What is zener voltage?
A zener diode has a voltage when it reachesbreak over it may be 5v 12vor other voltage as manufactured. The manufacture will produce a 5v zener or is it? This voltage can change from device to device but the mean or nominal voltage will be as close as 5v as possible. So when buying a 5v zener do not expect 5v absolute but a nominal 5 v ZENERS are designed for a specific voltage [ THEREFORE NOMINAL] as mentioned above . depends on the voltage required it can be bought within a specific voltage -/+ a % of the breakdown
What happen if 440V is connected to 220V transformer?
If the frequency is kept the same, you will overexcite the transformer, and it will draw excessive current (similar to inrush currents). Insulation tests are performed on transformers above nominal voltage, but they are performed at higher than rated frequency to keep the volts per hertz roughly equal to prevent overexciting the core.
Can a 240v - 110v stepdown transformer be reversed to supply from180V stepping up to 240Volts?
Transformers can be reversed but their ratio remains the same. In this case a 240 to 120 volt step down transformer has a ratio of 2:1. By reversing the transformer and using 180 volts on the secondary side, there would be a potential of 360 volts on the primary side of the transformer. Also by using the higher voltage on the secondary side, stepping up will drive the primary side voltage above what the insulation factor that is recommended which is 240 volts.A 240/120 v transformer is designed to run at that voltage, and it is dangerous to operate it at a significantly higher voltage because there will be appreciably higher magnetic flux in the iron core, leading to higher power dissipation and a potential fire hazard.For a great explanation of how transformers operate, see related links below.
How can transformer oil be used in transformers with voltage rating above its breakdown voltage?
In this circumstance, the clearance between components at different potential must be increased.
Why line voltage at the secondary of transformer is above the required value?
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What do you mean by no load of transformer?
Transformers voltage ratings are typically at full load. For instance, A 24 VAC, 10A transformer will have a terminal voltage of 24 when it is feeding 10 amps to a load. Since the transformer windings have some resistance, the transformer designer has to wind the transformer to put out more than 24 volts, since some of the voltage will be lost, dropped across the resistance of the secondary windings. But, according to Ohm's law, the voltage dropped across a resistance is proportional to the current (E=IR). If we take away the 10A load, there is no current, and therefore no winding voltage drop! The excess voltage the designer built in now appears at the terminals. This is the no-load voltage. In my example above, when we remove the 10A load, the output voltage of the transformer might rise to 26.4V. We would say the no-load voltage of that transformer is 26.4V The ratio of full-load voltage to no-load voltage is called the transformer's "regulation factor". It is calculated as: (no-load voltage - full-load voltage) / full-load voltage * 100. Ours is: ((26.4 - 24) / 24) * 100 = 10%.
What are the conditions for operate the three phase transformer?
The BDV value of the transformer oil should be above 50kv winding resistance value should me minimum depends upon the KVA Of trans earthing should be provide for the trans air should be release inside of the tranformer insulation level should be check to operate the transformer these are all the initial condition to operate the trans
A transformer is a device used to increase or decrease dc voltage?
The answer below this is not correct, a transformer can only be used on AC not DC. So the statement, "A transformer is a device used to increase or decrease DC voltage" is false The above comment relates to an entry which was obviously deleted. However, the above comment is also false. The ignition coil in of a petrol engine is a transformer, a pulse transformer. It's d.c. which passes through the primary, not a.c. <<>> A: this is a passive component as opposed to a device that is active answer is yes it does that but more importantly it isolates and match in/out impedance's
How is 4160 voltage made?
Well first we need to generate voltage from electrical generator. Then if voltage are below 4160 volt step up Transformer is used and if voltage are above 4160 volt step down Transformer is used. Generally voltage produced from generator are low so we need to step up voltage to higher values such as 240 kilo volt to transmit them to longer distances to reduce power losses.
What is the capacitive voltage transformer in sub station?
A coupling capacitor voltage transformer (CCVT) is composed of two stacks of capacitors which step the primary voltage down to a lower voltage potential transformer. These are typically used on 100kV and above, and the potential transformer is often around 15kV on the primary side. There are two reasons to use CCVTs over PTs (potential transformers) - at the above voltage levels, they are cheaper, and they can be used for power line carrier signal injection. Under transient conditions, CCVTs typically won't perform as well as PTs, and also may have worse accuracy ratings, so are often not acceptable for metering purposes.
