Classification of Transformers
Transformers are constructed so that their characteristics match the application for which they are intended. The differences in construction may involve the size of the windings or the relationship between…
Transformer Coil Polarity
The symbol for a transformer gives no indication of the phase of the voltage across the secondary. The phase of that voltage depends on the direction of the windings around…
Transformer Operation Under No-Load
If the secondary of a transformer is left open-circuited (Figure 6), primary current is very low and is called the no-load current. No-load current produces the magnetic flux and supplies…
Transformer Losses and Efficiency
All transformers have copper and core losses. Copper loss is power lost in the primary and secondary windings of a transformer due to the ohmic resistance of the windings. Copper…
Three Phase Transformer Connections
So far, our discussion has dealt with the operation of single-phase transformers. Three-phase transformer operation is identical except that three single-phase windings are used. These windings may be connected in…
Transformer Current Ratio
The current in the windings of a transformer is inversely proportional to the voltage in the windings. This relationship is expressed in below Equation. where IP = primary coil current…
Transformer Voltage Ratio
The voltage of the windings in a transformer is directly proportional to the number of turns on the coils. This relationship is expressed in below Equation. where VP = voltage…
Transformer Theory of Operation
A transformer works on the principle that energy can be transferred by magnetic induction from one set of coils to another set by means of a varying magnetic flux. The…
Transformer Efficiency
Efficiency of a transformer is the ratio of the power output to the power input, as illustrated by Equation. where PS = power of secondary PP = power of primary…
Transformer Impedance Ratio
Maximum power is transferred from one circuit to another through a transformer when the impedances are equal, or matched. A transformer winding constructed with a definite turns ratio can perform…
