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A CT, or current transformer, has a specified current ratio. The 5 in your question is the current supplied to the metering instrument at full scale. CT's current ratio is always full scale to 5, for instance - 200:5, 3000:5, etc.
So, if a CT has a ratio of, say, 1000:5, this means when the conductor being measured is supplying 1000 amperes to the load, the CT will output 5 amperes to the instrumentation. The relationship is linear, so if the current is 500 amperes, the output will be 2.5 amperes, at 200 amperes the output will be 1 ampere, etc.
This is done so the instrument can be designed always the same, with a 5 ampere input, no matter what size current is to be measured. Otherwise you would have to order (and manufacture) many different models of meter, one for each current range.
The metering must be set, or programmed, with the CT multiplier, so it knows how much current is really flowing when it sees 5 amperes on the input.
Similarly, we use PT's or potential Transformers to reduce higher system voltages to a range that the instrument can also handle.
Wiki User
∙ 12y ago
Wiki User
∙ 11y agoThe ratio of CT 5 means that your meter show 5 times less than actual value. consiter your meter shows 10A then the actual value in the line is 50A. It is done because of limitation in measuring instrument. So we use CT to reduce the current of Actual in known ratio.
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What will happen if we use current transformer of different rating for each phase in three phase supply?
A current transformer has to have the same ratio as the meter that it drives. Full scale deflection on the meter is 5 amps which equals the maximum allowed current on the phase that it is reading. A different ratio on the CT to meter would show an erroneous reading on the meter depending on the ratio of the connected CT. To keep costs down the meter is common to all three phases and is read by connecting the meter to the phase CT through a three position switch.
What is the ratio of the energy a machine delivers to the energy supplied to it?
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The question is incomplete, because there are no mention about CT & PT ratios. 600VA 5 can not be CT ratio.
What is the formula for calculating wattage?
wattmeter is constructed such that it read only power on a single scale. Only single scale will avilable to read the measured power. In order to take the acuurate reading just we measure the reading and we will multiple along with factor called multificaion factor. That's depends on on which voltage knob we connected and also the current. Multification factor can be dtermind by: Multification factor =(voltage range*current range*pf)/Max scale deflection...
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The answer depends on what two (or more) things the ratio is meant to compare. The kinetic energy of several objects? The kinetic energy of an object compared to its total energy? The kinetic energy compared to its engine size?
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1 ratio 5 is the fixed ratio of atom in a molecules...
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Bit Energy-to-Noise Density (Eb/N0) is the ratio of bit energy to noise density. This value is used to specify the lower limit of operation in most digital communications systems and is also used to measure radio channel performance.
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How will you define energy meter constant?
The ct ratio of the coil and multiplying it with the meter kwh reading.
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It is 1000 : 1
What is the ratio for a meter to centimeters?
1:100
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1 square meter is 10.76391 square feet.
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What is an efficiency ratio?
The efficiency ratio for a machine usually refers to the ratio of the useful energy available from a machine and the energy put into it.
