TAP-CHANGING TRANSFORMERS There is some voltage loss in high-voltage distribution circuits. This means that the impressed voltage on the primary winding of a stepdown transformer may be lower than the primary voltage indicated on the nameplate. As a result, the secondary terminal voltage is also lower than the nameplate value. Because this condition is undesirable, […]
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Alternating current fundamentals
Transformers: Tap-changing transformers , Frequency and voltage , Transformer impedance and Transformer nameplate data.
TAP-CHANGING TRANSFORMERS There is some voltage loss in high-voltage distribution circuits. This means that the impressed voltage on the primary winding of a stepdown transformer may be lower than the primary voltage indicated on the nameplate. As a result, the secondary terminal voltage is also lower than the nameplate value. Because this condition is undesirable, […]
Continue reading…
Transformers: Magnetic domains , Multiple tapped windings and Cooling transformers.
MAGNETIC DOMAINS Magnetic materials contain tiny magnetic structures in their molecular material, known as domains. These domains can be affected by outside sources of magnetism. Figure 13–22 illustrates a magnetic domain that has not been polarized by an outside magnetic source. Now assume that the north pole of a magnet is placed toward the top […]
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Transformers: Magnetic domains , Multiple tapped windings and Cooling transformers.
MAGNETIC DOMAINS Magnetic materials contain tiny magnetic structures in their molecular material, known as domains. These domains can be affected by outside sources of magnetism. Figure 13–22 illustrates a magnetic domain that has not been polarized by an outside magnetic source. Now assume that the north pole of a magnet is placed toward the top […]
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Transformers: Transformer characteristics , Transformer construction and Transformer inrush current .
TRANSFORMER CHARACTERISTICS The characteristic curves of a 50-kVA transformer are shown in Figure 13–17. The efficiency of this transformer is very high even when the load is as low as 10% of the rated load. Note that the efficiency curve is nearly flat between 20% of the rated load to about 20% overload. The load–voltage […]
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Transformers: Transformer characteristics , Transformer construction and Transformer inrush current .
TRANSFORMER CHARACTERISTICS The characteristic curves of a 50-kVA transformer are shown in Figure 13–17. The efficiency of this transformer is very high even when the load is as low as 10% of the rated load. Note that the efficiency curve is nearly flat between 20% of the rated load to about 20% overload. The load–voltage […]
Continue reading…
Transformers: The single-phase,three-wire system.
THE SINGLE-PHASE, THREE-WIRE SYSTEM Nearly all residential and commercial electrical installations use a single-phase, three- wire service similar to the one shown in Figure 13–12. This type of service has a number of advantages: 1. The system provides two different voltages. The lower voltage supplies lighting and small-appliance loads, and the higher voltage supplies heavy-appliance […]
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Transformers: The single-phase,three-wire system.
THE SINGLE-PHASE, THREE-WIRE SYSTEM Nearly all residential and commercial electrical installations use a single-phase, three- wire service similar to the one shown in Figure 13–12. This type of service has a number of advantages: 1. The system provides two different voltages. The lower voltage supplies lighting and small-appliance loads, and the higher voltage supplies heavy-appliance […]
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Transformers:Polarity markings , ASA and NEMA standards , Transformers in parallel and The distribution transformer .
POLARITY MARKINGS The American Standards Association (ASA) has developed a standard system of marking transformer leads. The high-voltage winding leads are marked H and H . The low-voltage winding leads are marked X and X . The H lead is always located on the left-hand side when the transformer is faced from the low-voltage side. […]
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Transformers:Polarity markings , ASA and NEMA standards , Transformers in parallel and The distribution transformer .
POLARITY MARKINGS The American Standards Association (ASA) has developed a standard system of marking transformer leads. The high-voltage winding leads are marked H and H . The low-voltage winding leads are marked X and X . The H lead is always located on the left-hand side when the transformer is faced from the low-voltage side. […]
Continue reading…