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Chapter 13: Technical Aspects of Chargers and Current Transformers and Methods for Supervision

Battery chargers are employed for charging starter, traction, and stationary batteries as well as for supplying stand-by power. The demands for these devices are dependent on the operation conditions. Charging starter and traction batteries is mainly conducted during recesses. Hereby the consumers are disconnected for charging batteries (Figure 13.1). Charging for stationary batteries allows an ensured stand-by power supply for parallel and switch operation for DC consumers. | 13 Technical Aspects of Chargers and Current Transformers and Methods for Supervision G. WILL 13.1 APPLICATION OF BATTERY CHARGERS Battery chargers are employed for charging starter traction and stationary batteries as well as for supplying stand-by power. The demands for these devices are dependent on the operation conditions. Charging starter and traction batteries is mainly conducted during recesses. Hereby the consumers are disconnected for charging batteries Figure 13.1 . Charging for stationary batteries allows an ensured stand-by power supply for parallel and switch operation for DC consumers. For switch operation Figure 13.2 consumers are supplied by power through a rectifier or directly by three-phase supply. In the case of mains power failure the most important consumers are supplied with energy by the battery until the mains power returns. A charger then charges the battery. If the charging process is terminated a float-charge operation is activated so full capacity is available at any time. For parallel operation the consumer and the battery are permanently operated in parallel and supplied by their common charger Figure 13.3 . In case of mains failure the battery without interruption automatically supplies the consumer. Copyright 2003 by Expert Verlag. All Rights Reserved. Figure 13.1 Charging operation for starter and traction batteries. 13.2 CHARACTERISTIC VOLTAGES OF LEAD-ACID AND NiCd BATTERIES The characteristic voltage values for lead-acid and NiCd batteries are listed in Table 13.1. 13.3 CONSTRUCTION AND FUNCTION OF BATTERY CHARGERS Battery chargers can generally be divided into two main groups controlled and uncontrolled devices. 13.3.1 Controlled Battery Chargers 13.3.1.1 Thyristor Controlled Chargers These consist of the following Figure 13.2 Switch operation for charging stationary batteries. Copyright 2003 by Expert Verlag. All Rights Reserved. Figure 13.3 Parallel operation for charging stationary batteries. Transformer. Controllable .