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It is normal to ground the centre tap of a centre-tapped winding so that the live voltage on either end of the winding is minimised relative to earth.
In North America the 240 v secondary of a supply transformer has a grounded centre tap so that a property can be supplied with two separate 120 v circuits for lighting and other low-power use, while a 240 v supply can be taken from the two live wires for high-power use for cookers, aircon etc.
In Europe split-phase supplies are used in rural areas where a 460 v transformer-secondary is centre tapped and a 3-wire supply sent to a remote site with a neutral wire and two 230 v live wires. Alternate properties are connected to alternate live wires and if they all use the same current there is no current in the neutral wire going back to the transformer, and therefore no power is lost in the neutral wire.
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What is approximate turns ratio of the centre-tapped transformer used?
It depends on the voltage ratio of the transformer. If you know the primary and secondary voltages, then you can work it out for yourself.
Materials used in constructing a full wave rectifier?
Full wave rectifiers consist of two (for a center-tapped transformer) or four (for a single-ended transformer) diodes connected such that as the polarity of the AC input changes, the diodes steer the current flow so the output polarity does not change. The output of a FW rectifier is pulsating DC, which is normally then filtered or smoothed with a capacitor.
How you using ref relay in transformer?
an REF relay (restricted earth fault) is used to provide ground fault protection for a transformer. Its' operation is limited by CTs starred towards the transformer (usually on the transformer bushings or in breakers used to isolate the transformer), so it will only operate for transformer related faults. Because of this, it can be set to operate very quickly.
What is the difference between transformers and autotransformers?
A transformer or, more-properly, a mutual transformer, has two windings, the primary and the secondary, which are electrically-isolated from each other, with the secondary voltage induced through mutual induction. An autotransformerconsists of one tapped winding, so the secondary circuit is not electrically isolated from the primary circuit. An autotransformer may be used to either increase or decrease the primary voltage, depending how it is connected.
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).
Where are center tapped transformers used?
The transformer that feeds your house is a center tapped transformer. Primary 7200, Secondary 240. The 240 volt secondary is center tapped to give you 120 volts on either side of the tap. Hence house voltage is 120 / 240 volts.
Why are center tapped transformers used in North America?
Center tapped transformers are used in North America to be able to use two voltages from the transformers secondary. It is known as a three wire system. Appliances circuits that utilize 240 volts and appliances that use 120 volts can be supplied from one transformer. The transformers secondary is center tapped and grounded. This allows the 240 volt winding L1 - L2 to produce 120 volts from one leg of the winding to ground L1 - N and the second half of the winding 120 volts from N - L2. <<>> Center tapped transformers are used anywhere world wide where ever they were designed to be used. There is nothing particular to a center tapped transformer that makes it more or less suitable for use in North America.
Why diodes are used after center tapped transformer in dc to ac inverter?
Diodes are used after a center-tapped transformer in a DC to AC inverter to rectify the alternating current (AC) output of the transformer into pulsating direct current (DC). This rectified voltage is then smoothed using filters to produce a more stable DC waveform. The diodes act as one-way valves, allowing current to flow in only one direction, thus converting the AC voltage into a pulsating DC voltage.
What is approximate turns ratio of the centre-tapped transformer used?
It depends on the voltage ratio of the transformer. If you know the primary and secondary voltages, then you can work it out for yourself.
Why is voltage of supply decreased before entering your homes?
In the US a service drop transformer (on the pole or underground) converts the distribution voltage to 220VAC center tapped, which provides two opposite phased 110VAC outlet and lighting use and/or one 220VAC single phased high power for heating and cooking use. Occasionally 230VAC center tapped or 240VAC center tapped is provided instead of 220VAC.
Can the two end of a center tap transformer be use with out a rectifier?
The twoends of a center tap transformer cannot be used without a rectifier.
How you differentiate between single phase and three phase transformer?
A single-phase transformer works with a single-phase supply, while a 3-phase transformer is used with a 3-phase supply. A single-phase transformer has 2 wires on the primary and secondary (ignoring taps) while a 3-phase tansformer has 3 or 4 wires on the primary and secondary.
In the event the transformer overheats and the transformer high temp illuminates the secondary distribution center can not be used under any circumstances?
False
Materials used in constructing a full wave rectifier?
Full wave rectifiers consist of two (for a center-tapped transformer) or four (for a single-ended transformer) diodes connected such that as the polarity of the AC input changes, the diodes steer the current flow so the output polarity does not change. The output of a FW rectifier is pulsating DC, which is normally then filtered or smoothed with a capacitor.
How you using ref relay in transformer?
an REF relay (restricted earth fault) is used to provide ground fault protection for a transformer. Its' operation is limited by CTs starred towards the transformer (usually on the transformer bushings or in breakers used to isolate the transformer), so it will only operate for transformer related faults. Because of this, it can be set to operate very quickly.
Why a full wave rectifier is preferred over a half wave rectifier?
The a.c. component, or ripple, produced by the 4-diode (full wave) bridge rectifier is the same as that produced by the 2-diode full wave rectifier. The bridge is connected across the secondary winding of a transformer. The 2 diodes of the other type of full wave rectifier are each connected to one end of a winding, but that winding requires a center tap. For any desired value of d.c. after rectification, the a.c. voltage of the 2-diode rectifier winding has to be twice that of the winding required for the bridge.
Are a tapped transformer and a step-down transformer the same?
Transformers can be used in either step-up mode or step down mode, they are just as efficent connected either way. Most large transformers have percentage "taps" to allow voltage corrections up or down by about 15%.
