Single Phase Transformers 1
Single Phase Transformers
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Question1
a low voltage winding connected in delta or in star connection?
Star
Question2
A Magnetic field can Produce by what?
Coil
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video
Introduction
A transformer is a device for increasing or decreasing an AC voltage.
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Constructional Features of Single-Phase Transformers
A transformer consists of two coils of wires known as primary and secondary windings.
Where:
• VP - is the Primary Voltage
• VS - is the Secondary Voltage
• NP - is the Number of Primary Windings
• NS - is the Number of Secondary Windings
• Φ (phi) - is the Flux Linkag
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Constructional Features of Single-Phase Transformers
A single-phase transformer can operate to either increase or decrease the voltage applied to the primary winding.
1) When a transformer is used to “increase” the voltage on its secondary winding with respect to the primary, it is called a Step-up transformer.
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Constructional Features of Single-Phase Transformers
2) When it is used to “decrease” the voltage on the secondary winding with respect to the primary it is called a Step-down transformer.
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Constructional Features of Single-Phase Transformers
3) a third condition exists in which a transformer produces the same voltage on its secondary as is applied to its primary winding.
This type of transformer is called an “Impedance Transformer”
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According to the design, transformers can be classified into two:
1. Core- Type Transformer. 2. Shell-Type Transformer.
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Oil Filled Self-Cooled Type.
Oil Filled Water Cooled Type.
Air Blast Type.
According to the type of cooling employed
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Question
On the outside of the transformer there are components what are the function of them?
1. Some help it to remain at a good working temperature.
2. Some help make it safer in the event of accident.
3. Some are used for monitoring.
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Theory of Operation The operation of a transformer is based on two principles:
1. A voltage is induced in a conductor when the conductor passes through a magnetic field.
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2. A current passing through a conductor will develop a magnetic field around the conductor.
Theory of Operation
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Question
True Or FalseThe winding which is connected to the supply mains is known as Secondary winding ( × )
The winding which is connected to the load is known as Primary winding ( × )
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video
Ideal of Transformers • Two magnetically coupled coils
• Primary: N1 turns
• Secondary: N2 turns
• Primary and secondary can be arbitrarily assigned
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Ideal of Transformers
Ideal assumptions
• No flux leakage.
• No eddy currents. Recall from magnetic circuits lecture
• No winding resistance.
• Near infinite core permeability.
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EMF equation and transformation ratio.
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Voltage Transformation Ratio (K)
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1. A 50Hz transformer primary voltage of the screw 300 and 5000, determining the taxa. Mutual flux Φm.b. If the 230 V secondary voltage of the secondary screw.Are,ƒ = 50Hz has been invokedNp = 5000 Qm =?Ep = 2300 Volt Ns =?Es = 230 Volt
A. Ep = 4.44 ƒNpΦ
Φ = Ep / 4.44ƒNp
= 2300/4.44 × 50 × 5000
= 2.09 mweb. Ans.
B. Es = 4.44 ƒNsΦ
Ns = Es / 4.44ƒΦ
= 230 / 4.44 × 50 × 2.09mweb
= 500 Ans
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