Three Phase Technology Auxiliary Circuit PDF

5. AUXILIARY CIRCUIT DESCRIPTION The auxiliary circuit in WAP5 and WAG9 locomotives has single phase as well as 3-phase auxiliary motors. The circuits feeding the single phase machines and 3-phase machines are distinctly separated although they are fed from on...

5. AUXILIARY CIRCUIT DESCRIPTION The auxiliary circuit in WAP5 and WAG9 locomotives has single phase as well as 3-phase auxiliary motors. The circuits feeding the single phase machines and 3-phase machines are distinctly separated although they are fed from one and the same auxiliary winding (1000V) of the main transformer. SINGLE PHASE CIRCUIT The single phase auxiliary circuit is shown in Fig.5.1. An auxiliary transformer to give 415V and 110V AC output steps down the auxiliary winding voltage. The following loads are connected in the 415V AC circuit:  Machine room blowers.  Scavenge blowers for machine room blowers.  Cab heaters. Loads connected to the 10V AC circuit are:  Cab fans.  Blowers for cab heater. The 415V and 110V AC auxiliary circuits energized as soon ad VCB is closed. The machine room blowers cool different electronic cubicles in the locomotive in addition to provide for pressurisation of the machine room. For working control electronics a machine room temperature below 70°C is to be ensured. In peak summer periods, if the locomotive with all the doors and window closed is kept under the sun for a long time, there is a possibility that the machine room temperature exceeding 70°C. Provision of a “cooling mode” operation in the control circuit facilitates raising of pantograph and closing of VCB in such an eventually without intervention of control electronic. The machine room blower starts working to bring down the machine room temperature after which the locomotive can be operated in the normal “driving mode”. 3-PHASE CIRCUIT The overview of the 3-phase auxiliary circuit is shown in Fig.5.2 for running the 3-phase auxiliary motors, WAP5 and WAG9 locomotives are equipped with 3-phase static auxiliary converters to supply the auxiliary machines of the locomotive. The static auxiliary converter is very different in principle, construction and operation from the conventional Arno Converter. Since there are no rotating parts as in the Arno Converters, these converters have less wear and tear, thus making it almost maintenance free. CIRCUIT DESCRIPTION The load distribution among the BURs is such that required redundancy is achieved by automatically switching load from one auxiliary converter to another in case of failure of any TRACTION ROLLING STOCK : THREE PHASE TECHNOLOGY Page 60 one auxiliary converter. BUR1&2 feed variable voltage and variable frequency supply to the traction motor bowers; oil cooler blowers and its scavenger blower of bogie1 & bogie2 respectively. BUR3 feeds a fixed frequency supply to the two compressor motors and two converter and transformer oil pumps. In addition to that, BUR3 also feeds the battery charger. For traction motor blowers, oil cooler blowers and their scavenge blowers, the speed is controlled in three steps (17Hz, 33Hz & 50Hz) by the control electronics depending on the temperature of the traction motors / cooling oil sensed by temperature sensors in traction stator and in oil cooling circuit. BUR3, on the other hand, is operated at a fixed frequency of 50Hz to feed the drive motors of the main compressors, oil pumps in addition to the battery charger. The output voltage of Bur3 varies a little around 415V depending on the battery charging requirement. However, whenever a compressor starts, the output voltage and frequency of BUR3 are reduced to near zero and then ramped upto the full values to achieve a soft start of the compressors. Load changeover from one auxiliary converter to another in case of isolation of any one auxiliary converter to another in case of isolation of any one auxiliary converter is done automatically by the auxiliary converter electronics with the aid of electro-pneumatic contactors. If BUR1 fails and gets isolated, BUR2 feeds the auxiliaries for ventilation of both the bogies up to a maximum frequency limited to 42Hz. If BUR2 fails & gets isolated, BUR1 feeds the auxiliaries for ventilation of both the bogies up to a maximum frequency limited to 42Hz. If BUR3 fails and isolated, BUR2 feeds the compressor motor, oil pumps and the battery charger at affixed frequency of 50 Hz and BUR1 feeds the auxiliaries for ventilation of both the bogies up to a maximum frequency limited to 42 Hz. As shown in Fig.2, under normal operation, contactors 52/1, 52/3 52. ½, 52/5 are closed and contactors 52/2, 52/4, 52.1/1 are open. When BUR1 is isolated, contactors 52/4, 52/1, 52/3 and 52.1/2 are closed and 52/5, 52/2 and 52.1/1 are open. When BUR2 is isolated, contactors 52/5, 52/4, 52/3 and 52.1/2 are closed and 52/1, 52/2 & 52.1/1 are open. When BUR3 isolated, contactors 52/2, 52/4, 52/5 & 52.1/1 are closed and 52/1, 52/3 & 52.1/2 are open. TRACTION ROLLING STOCK : THREE PHASE TECHNOLOGY Page 61  Fig. 5.1 Single Phase Auxiliary Circuit TRACTION ROLLING STOCK : THREE PHASE TECHNOLOGY Page 62  Fig. 5.2 Overview of Three Phase Auxiliary Circuit TRACTION ROLLING STOCK : THREE PHASE TECHNOLOGY Page 63