Electricity supply rectifier equipment

Power Supply Electrical precipitators are generally energized by rectified alternating current of commercial frequency. The voltage is stepped up to the required value by means of a transformer and then rectified. The rectifying equipment has undergone an evolution which began with the synchronous mechanical rectifier in 1904 and was... 

The electrical supply equipment is the second biggest equipment package after the mechanical equipment. The package includes the transformer/rectifier (T/R) sets and bus bars for providing DC power to the cells, the associated power factor correction equipment and harmonics filtration equipment, and the service transformers and circuitry. This equipment will typically comprise about 15 - 25 % of the cellhouse cost. The cost is heavily influenced by whether or not an electrical substation is included, and by the redundancy requirements for the T/R sets. A plant can choose to have no spare T/R capacity, partial redundancy, or full redundancy. Such cost savings must be weighed against the cost of lost production when a T/R set fails. 

Consider as a further example an electrical supply for the memory in a data system. In order not to lose data in case of a.c. supply failure, certain data systems are fitted with self-contained emergency power supplies for relatively low powers. Data systems are generally supplied from the a.c. supply and are particularly sensitive to very short breaks and transient voltage variations. To overcome the weaknesses of the a.c. supply, there are various types of equipment, in particular inverters, supplied by battery-charger combinations. The inverter derives its supply with a.c. supply present from the rectifier and with a.c. supply absent from the battery. 

Another situation where caution must be exercised is when equipment is energized from more than one point. (A good example is a DC trolley line in which rectifiers supply the trolley wire at various points along the trolley.) In these types of situations, all possible sources of electricity must be recognized and all disconnecting devices must be locked and tagged. 

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