Electrical installation transformers

Similarly, all electrical installations (transformers, metering panel, incoming high tension supply, etc.) are to be thoroughly cleaned, overhauled, and offered for inspection. The instmctions from electrical inspector shall also be complied with, and aU facilities tested. 

The electrical installation consists of four major components, namely, power wiring, lighting, transformation and service, and instrument and control wiring. Table 9 shows these component costs as ratios of the total electrical cost... 

Internal fnses and internal over-pressure disconnections for shunt capacitors. Application gnide for power transformers Specifications for conduits for electrical installations. 

Substation - An electrical installation containing power conversion (and sometimes generation) equipment, such as transformers, compensators, and circuit breakers. 

Consumers with large energy requirements often find it more economical and convenient to receive electricity at 11 kV and to transform it down to the lower values as required. In all cases, however, it is essential that the consumer s electrical installation and equipment, both fixed and portable, meet good standards of design, conshuction and protection, are adequately maintained and correctly used. 

The efficiency of an induction furnace installation is determined by the ratio of the load usehil power, P, to the input power P, drawn from the utihty. Losses that must be considered include those in the power converter (transformer, capacitors, frequency converter, etc), transmission lines, cod electrical losses, and thermal loss from the furnace. Figure 1 illustrates the relationships for an induction furnace operating at a constant load temperature with variable input power. Thermal losses are constant, cod losses are a constant percentage of the cod input power, and the usehd out power varies linearly once the fixed losses are satisfied. 

Power Supplies and Controls. Induction heating furnace loads rarely can be connected directiy to the user s electric power distribution system. If the load is to operate at the supply frequency, a transformer is used to provide the proper load voltage as weU as isolation from the supply system. Adjustment of the load voltage can be achieved by means of a tapped transformer or by use of a solid-state switch. The low power factor of an induction load can be corrected by installing a capacitor bank in the primary or secondary circuit. 

Although transformers suitable for other industrial installations are generally suitable for producing applications, certain options may be desirable— primarily due to environmental considerations. At locations subject to harsh environmental conditions, and particularly at locations subject to washdown with high-pressure hoses, non-ventilated enclosures are desirable, if not necessary. Likewise, at locations subjected to salt water and salt-laden air, it often is desirable to specify copper windings and lead wires. Most manufacturers provide standard units with aluminum windings and lead wires. Even if aluminum coils are used, it is almost always desirable to require stranded copper lead wires. This will lessen corrosion and loose terminal problems when transformers arc interconnected to the facility electrical system with copper conductors. If the transformers are to be installed outdoors in corrosive environments, cases should be of corrosion-resistant material (e.g., stainless steel) or be provided with an exterior coating suitable for the location. 

This chapter introduces the basic items of design and specification for the principal systems and components of an electrical industrial installation. Electrical supply systems are discussed with regard to interface with the supply authorities and the characteristics. Salient features of switchgear, transformers, protection systems, power factor correction, motor control equipment and standby supplies are identified and discussed together with reference to the relevant codes of practice and standards. The equipment and systems described are appropriate to industrial plant installations operating at typically 11 kV with supply capacities of around 20MVA. 

Electrical This item consists of transformers, wiring, switching gear, as well as instrumentation and control wiring. The installed costs of the electrical items may be estimated as 20 to 40 percent of the delivered equipment costs or 5 to 10 percent of the fixed capital investment for preliminary estimates. As with piping estimation, the process design must be well along toward completion before detailed electrical takeoffs can be made. 

The impedance can be measured using various instalments and techniques, ranging from a simple oscilloscope display to a fast Fourier transform (FFT) analyzer. The most common instrument used is a frequency response analyzer (FRA), e.g., the Solartron FRA. A potentiostat or a load bank combined with a frequency response analyzer can perform the EIS measurements. The electrical connection between the FRA, the potentiostat (or the load bank), and the fuel cell is illustrated in Figure 3.19. 

The classic Ex i-isolator is an associated apparatus for installation in a safe area. In this case, too, Zener diodes and resistors are used for voltage and current limitation. However, the components may be rated lower, since the components inserted for galvanic isolation are able to transfer only a limited (e.g. transformers) or absolutely no electric power (e.g. optocouplers). For the maximum voltage Um, the above-mentioned is valid concerning safety barriers. 

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