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What is a current transformer and how can a current transformer be used to extend the range of a wattmeter?
Wiki User
∙ 12y ago
A current transformer (CT) works just like any other transformer. It is important to note it is not referenced to ground. It reflects current flow, not phase to ground voltage, so it attempts to hold current constant, not voltage.
There is usually one primary "winding": one large cable through a donut CT, and multiple secondary windings. If a secondary winding is shorted (a wire placed across its terminals), the voltage built up in the secondary will be equivalent to V = I*Z, where I is the secondary current, and Z is the impedance of the secondary winding, usually specified as some flat value plus so many ohms per winding.
If too big of an impedance is placed on the secondary, a voltage will build up to the point that the donut CT saturates, resulting in an output wave that has a large amount of harmonics. If the CT is open circuit\'d, voltage will build up until it is high enough to arc over (usually where it should have been shorted). CT\'s can be damaged by open circuiting them, so don\'t do it.
Wiki User
∙ 12y ago
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What is the ampere range value of transformer?
This typically has to do with how many amps you can safely pull from the secondary of the transformer.
what are the advantage of current transformer?
These are used with low range ammeters to measure current in HVAC 's where direct connection of instruments is impratical. They not only insulate the instruments from HV lines but also step down current in a known ratio. ( i .e . ) Iline =(I1 \I2) * Ammeter Reading where Iline = Line Current I1 \I2 = Current Ratio
Can instrument transformers be used to extend the range of a moving coil voltmeter?
Not directly, as MC instruments are direct-current instruments, whereas instrument transformers only work on a.c.
What is one of most common uses of transformer?
Both Current and Potential Transformer are instrument Transformers which are used to measure very high current and voltage respectivly. Current Transformer is a Step up transformer and used to measure high current, its secondry is connected to ammeter of very small capacity (usally 5 A) but its Scale is calibrated according to actul values. Potential Transformer is a step down tansformer and its secondry is connected to voltmeter of small range but again the scale is calibrated for actul values. So as a whole both Current and Potential Transformers are used to measure high values of Current and Voltage respectivly.
What is the difference between electronic and magnetic transformer?
All transformers are magnetic. A transformer is two (or more) coils of wire wound together. The varying magnetic field created by the primary winding induces a current in the secondary coils proportional to the ratio of the number of turns. You're probably refering to a switchmode powersupply as a "electronic transformer" (which is bad nomenclature, by the way). A switch mode supply actually contains a normal transformer in its core, along with circuitry to allow for a wide input fange and a narrow output range.
How do you increase current capacity of an ammeter?
In measuring high AC currents a current transformer with a suitable rating say 100/5 or 1000/5 are used. The secondary current is usually 5 amps when the fulload current of 100 or 1000 as the case may be is flowing in the mains. It is the univerasl practice to use CT's for measurement of AC currents. In DC circuits the transformer method will not work, so to increase the current that you can measure you can allow a known amount of current to bypass the ammeter and recalibrate the ammeter. In other words, put a shunt in parallel with the ammeter.
How does current transformer works in a substation?
A current transformer works on the same principle as that of a simple transformer however it steps down the high current into a low level so that it can be measured using an ammeter of a suitable range. In some current transformers extra cores are provided. This is done in order to prevent the faulty currents i.e. the over currents, earth faults, differential protections. The extra cores of a C.T. gets saturated as soon as the faulty currents starts flowing and thereby does not harm the main core of the transformer and the ammeter connected. The C.T. is always connected in the line carrying current. It first steps down the current to a measureable form and further gives this current to the ammeter.
What is the oil capacity of a transformer?
Depends on the transformer. This can range from a few gallons to thousands of gallons.
Can I buy a cable to extend the range of my wireless mouse's transmitter?
There is not a cable that can extend the range of a wireless mouse.
What is the ampere range value of transformer?
This typically has to do with how many amps you can safely pull from the secondary of the transformer.
How do you multiply current transformer output?
There are many ways but never can you multiply the power. <<>> A current transformer is specifically designed, by amp turns, to only output 5 amps. Meters that are connected to CT's have a full range deflection (scale) of 5 amps. To do what you are asking seems pointless as there are no meters with 10 amp full scale deflection.
How shunt helps to extend the range of ammeter?
A shunt is connected in parallel with an ammeter. Any current applied to parallel devices will divide betwen them, so the ammeter will pass only a part of the total current.
What is a variable transformer?
A variable transformer is capable of changing its output voltage from 0 to maximum output or over a specific range. It is also named an adjustable transformer.
Extension of a range of ammeter using a current transformer?
typically the ratio is on the current transformer it will say something like 100:5 witch means 5a meter becomes 100A full scale the 5 instead of a 1 gives you a hint about the capacity of the transformer its 20:1 so you could use it to make a 1A meter into a 20A but making a 10A meter into a 200A may lead to problems (accuracy or power)
What is the definition of audio-frequency transformer?
An audio frequency transformer is a transformer designed to operate in the range of frequencies audible to the average human. This range is generally accepted to be from 20 Hz to 20,000 Hz. The usual purpose of an audio transformer is to match impedances between circuit sections. For example: between a microphone and the input of an amplifier, (input transformer), or between the output of an amplifier and the loud speaker. (output transformer).
How could you extend the range of value data represent?
We extend the range of values by changing the data types. Such as if a variable declare by int data type It's range between -32768 to 32766. We can extend it's range by change the type long or other. If we change long then its range between -2147483468 to 2147483467.
How does a current transformer work?
A current transformer is used in high voltage circuits where it is not possible to measure current directly. A CT is a step up transformer with only one turn in primary. There will be as many cores based on the purposes like metering, protection etc. The secondary of a CT should never be kept open circuited bcoz very high flux will be developed in the secondary and hence it may be damaged.
