CONSTANT-CURRENT TRANSFORMERS Street lamp circuits may be connected in series or in parallel. The method used depends on the policies of the local utility company. If the lamps are connected in series, some method must be provided to short out any defective lamps. Remember that if one lamp in a series circuit burns out, all […]
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Alternating current fundamentals
Special Transformer Applications : Constant-current transformers .
CONSTANT-CURRENT TRANSFORMERS Street lamp circuits may be connected in series or in parallel. The method used depends on the policies of the local utility company. If the lamps are connected in series, some method must be provided to short out any defective lamps. Remember that if one lamp in a series circuit burns out, all […]
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Special Transformer Applications : Autotransformers .
AUTOTRANSFORMERS The conventional transformer has separate primary and secondary windings that are electrically insulated from each other. The autotransformer, on the other hand, has a primary winding and a secondary winding in the form of one continuous winding. This winding is tapped at certain points to obtain the desired voltages. The winding is wound on […]
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Special Transformer Applications : Autotransformers .
AUTOTRANSFORMERS The conventional transformer has separate primary and secondary windings that are electrically insulated from each other. The autotransformer, on the other hand, has a primary winding and a secondary winding in the form of one continuous winding. This winding is tapped at certain points to obtain the desired voltages. The winding is wound on […]
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Special Transformer Applications : Instrument transformers.
Special Transformer Applications INSTRUMENT TRANSFORMERS Instrument transformers are used with instruments and relays to measure and control ac circuits. Large and expensive devices are required to measure high voltages and currents directly. However, instrument transformers used with small standard devices provide a way of measuring high voltage and current values safely. The use of instrument […]
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Special Transformer Applications : Instrument transformers.
Special Transformer Applications INSTRUMENT TRANSFORMERS Instrument transformers are used with instruments and relays to measure and control ac circuits. Large and expensive devices are required to measure high voltages and currents directly. However, instrument transformers used with small standard devices provide a way of measuring high voltage and current values safely. The use of instrument […]
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Transformer Connections for Three-Phase Circuits: Bus ducts and panel problems.
BUS DUCTS AND PANEL PROBLEMS Triplen harmonic currents can also cause problems with neutral bus ducts and connecting lugs. A neutral bus is sized to carry the rated phase current. Because triplen harmonics can cause the neutral current to be higher than the phase current, it is possible for the neutral bus to become overloaded. […]
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Transformer Connections for Three-Phase Circuits: Bus ducts and panel problems.
BUS DUCTS AND PANEL PROBLEMS Triplen harmonic currents can also cause problems with neutral bus ducts and connecting lugs. A neutral bus is sized to carry the rated phase current. Because triplen harmonics can cause the neutral current to be higher than the phase current, it is possible for the neutral bus to become overloaded. […]
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Transformer Connections for Three-Phase Circuits: Harmonics and Circuit breaker problems .
HARMONICS Harmonics are voltages or currents that operate at a frequency that is a multiple of the fundamental power frequency. If the fundamental power frequency is 60 Hz, for example, the second harmonic would be 120 Hz, the third harmonic would be 180 Hz, and so on. Harmonics are produced by nonlinear loads that draw […]
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Transformer Connections for Three-Phase Circuits: Harmonics and Circuit breaker problems .
HARMONICS Harmonics are voltages or currents that operate at a frequency that is a multiple of the fundamental power frequency. If the fundamental power frequency is 60 Hz, for example, the second harmonic would be 120 Hz, the third harmonic would be 180 Hz, and so on. Harmonics are produced by nonlinear loads that draw […]
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