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Why autotransformer can handle more power than conventional transformer?
Wiki User
∙ 14y ago
Perhaps you're referring to the size of the core? Strictly speaking, a 30MVA autotransformer can handle the same amount of power as a conventional transformer.
But an autotransformer will be smaller than an equivalent conventional transformer. The reason is an autotransformer essentially has one winding on a core, with one tap including the whole winding, and another tap including only part of the winding. In a conventional transformer, power is transferred from one winding to the other by induction. In an auto, some is by conduction, and some is by induction.
Here's an example comparison:
Say we have a 10MVA 100kV/50kV 3 winding auto transformer. There are two parts of the winding - the series winding (the section of winding between the 100kV connection and 50kV connection), and the common winding (the section of winding between the 50kV connection to the neutral). If powered at 10MVA (full load), there will be:
10M / (100k * sqrt(3)) = 57.7 Amps flowing into the primary, and
10M / (50k * sqrt(3)) = 115.5 amps flowing out of the secondary
So, 57.7A flow into the primary, down through the series winding and out the secondary. At the same time 57.7A flow up from the neutral through the common winding and out the secondary, resulting in a total secondary current of (57.7 + 57.7) = 115.5 (sorry, rounding is making my math look wrong!).
Thus, the series winding is handling a total of:
(100k - 50k)* 57.7A*sqrt(3) = 5MVA, and the common winding is handling a total of:
(50k - 0) *57.7A*sqrt(3) = 5MVA
So the series and common windings only have to be made to handle 1/2 the total load(for this example - it is 1/2 because the primary / secondary voltage is 2/1). In a conventional transformer, each winding carries the full load (10MVA), because it operates on induction (no conduction).
If the votlage ratio between primary and secondary is too high, there is no real net savings in size (and thus cost), so a conventional transformer is often used. The cutoff point is around 4.
Wiki User
∙ 14y ago
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What function does a capacitor serve in an auto transformer?
An autotransformer does not normally use any capacitors as it is a transformer with one winding and the lower voltage is taken from a tap part-way up the winding. A capacitor could be added if there is a concern about the power factor presented by the autotransformer to the supply.
What is the difference between power transformer and instrument transformer?
A power transformer is used to provide power (to your home, for example), an instrument transformer is used to measure voltage or current (for metering, for example).
What is the difference between Auto transformer and Power transformer?
An auto transformer has one winding with the output being tapped at some point and therefore has no isolation between primary and secondary. This may make it unsafe or illegal in some applications. A common power transformer has separate windings.
How a rectifier transformer deffer from a power transformer?
rectifier transformer converts acinto dc.but,power transformer convert step up or step down ac energy without changing frequency
Bil of power transformer?
B.I.L. stands for Basic Impulse Level for the transformer. It should be on the faceplate of the transformer.
What function does a capacitor serve in an auto transformer?
An autotransformer does not normally use any capacitors as it is a transformer with one winding and the lower voltage is taken from a tap part-way up the winding. A capacitor could be added if there is a concern about the power factor presented by the autotransformer to the supply.
Advantages of autotransformer?
the power can flow either way through autotransformer (345/120 kV) ?
How do you calculate power for a delta connected three phase autotransformer?
The maximum power output of the transformer is measured in VA or KVA, (volt-amps) or thousand (volt-amps). That will will marked or stamped on the transformer. If you want to measure the amount of power being used by the Xformer, measure the Line side current in amps with an amprobe and multiply by the line voltage to it. The result in watts is the power consumption.
Can 240 volts be converted to 110 volts?
Yes , with a step down transformer. 240 volts into the primary side H1 and H2 which is stepped down to 120 volts on the secondary side, X1 and X2.
How can auto transformer be differentiated from a two winding transformer just by looking at it externally?
A two-winding transformer must have at least 4 wires, an autotransformer need only have three. So, if the device has only three connections, it cannot be a two-winding transformer. Or, if it is, it is internally connected as an autotransformer and is treated the same. On the other hand, if it has four or more connections, it could be either, because the manufacturer could have internally brought out the common wire to two connections to make it easier to wire the line and load. You would have to measure with an ohmmeter to be sure! Warning! Do not attempt to make any such measurements unless you are trained and fully qualified to do so. If it is a large transformer used in a power distribution system it will have this information on the nameplate.
What is that black box in a laptop power cord?
That is a transformer, it lowers the voltage coming from the plug to a lower voltage that the laptop can handle.
What is meant by the term ideal transformer?
ideal transformer is that which has no power losses.if any transformer transfer power to secondary without power loss then that call a ideal transformer
Is transformer an amplifier?
No. In an amplifier, Power Out > Power in. In a transformer Power Out ~= Power In (minus internal losses). An AC generator is more like an amplifier than a transformer.
What is the difference between power transformer and instrument transformer?
A power transformer is used to provide power (to your home, for example), an instrument transformer is used to measure voltage or current (for metering, for example).
What will happen you f the rated power of transformer is changed?
You cannot 'change' the 'rated power' of a transformer except by changing the transformer for another one. You can, though, operate the transformer below its rated power or, for short periods of time, operate the transformer aboveits rated power.
What is meant by the term transform?
ideal transformer is that which has no power losses.if any transformer transfer power to secondary without power loss then that call a ideal transformer
What is the difference between Auto transformer and Power transformer?
An auto transformer has one winding with the output being tapped at some point and therefore has no isolation between primary and secondary. This may make it unsafe or illegal in some applications. A common power transformer has separate windings.
