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WAP - 4 is a common electric locomotive used in India. It is capable of hauling 26 coaches at a speed of 140 km/h. The locomotive was developed, after a previous class WAP-1 was found inadequate to haul the longer, heavier express trains (24 - 26 coaches) that were becoming the mainstay of the Indian Railways network. It was introduced in 1994, with a similar bodyshell to the WAP-1 class, but with Hitachi traction motors developing ( starting). Electricals are traditional DC loco type tap changers, driving 6 traction motors arranged in Co-Co fashion. This locomotive has proved to be highly successful, with over 800 units in service and more being produced. Newer examples have been fitted with Microprocessor Controlled diagnostics, Static Converter units (instead of arnos) and roof mounted Dynamic (Rheostatic) Brakes. The locomotive can be seen in service across the electrified network of Indian Railways and are homed at 14 sheds (depots). == Design == The loco has a streamlined twin cab carbody design, with top-mounted headlamps. The first 150 or so units had the headlamp mounted at waist level, with the lights being mounted in a protruding nacelle. Some earlier locos, especially from the Erode loco shed have the headlamps placed on the top. Later on the headlamps were placed in a recessed nacelle, and from road # 22579 onward, the headlamps were moved to the top. Also they have digital notch repeaters. Newer locos also feature larger windshields, more spacious driver cabin with bucket type seats and ergonomic controls. The control panel also features a mix of digital and analog displays in newer units (all analog display in older versions). The loco features higher power rated silicon rectifiers and indigenously-designed 5400 kVA transformer coupled with Hitachi HS15250 traction motors. Starting power is , with being supplied continuously. Original units were weighed 120 tonnes, which was brought down to 112 tonnes through the usage of lighter material. Some of the WAP-1 and WAP-3 and all the WAP-6 units were rebuilt to WAP-4 specifications after replacing the bogies & electricals. It has different underframe for handling larger buffing loads. Some units are fitted with speed recorders and some changes to control electronics. Some units also have data recorders for energy consumption. Some are even fitted with windshield washers. Few were provided with signalling lamps. Technical variants include WAP-4E which are probably fitted with electronic sensor for sensing loss in pressure in pipes. The Hitachi traction motors are the ones used on freight engines. It was a challenge to put these in a passenger engine due to weight constraints. So the transformer is aluminum foil-wound and aluminum chequered plates are used for reducing the weight. These traction motors were more reliable so WAP-7. 415 volts, 3 phase, 50Hz power supply is used to drive various auxiliary motors like (i)Traction motor blowers (2) Transformer radiater blower (3) Transformer oil pump (4) Smoothing Reactor Blowers (5) Silicon Rectifier Blowers (6) Battery charger. The 3 phase, 415 volt supply is obtained from single phase supply by Arno converter or Static converter. Indian railways has installed microprocessor based fault diagnostic system and Vigilance Control Device for the enhancement of safety and reliability of electric Locomotives. Some of the Newly manufactured WAP-4 locomotives also have air conditioning system for the comfort of loco pilot. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Indian locomotive class WAP-4」の詳細全文を読む スポンサード リンク
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