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| aspiration = Roots-type supercharger | tractionmotors = 4 × D77/78 DC | cylindersize = | cylindercount = 12 | trucks = | locoweight = | generator = D32 | builddate = February 1974–November 1980 | totalproduction = 351 }} The EMD MP15DC was a switcher-type diesel locomotive model produced by General Motors' Electro-Motive Division between March 1974 and January 1983. 351 examples were built. A MP15AC variant, with an AC drive, was also offered. Between August 1975 and August 1984 246 MP15ACs were built, including 25 for export to Mexico, and four built in Canada. The MP15DC replaced the SW1500 in EMD's catalog, and is superficially very similar to the predecessor model, using the same engine (a V12 EMD 645-series powerplant) in a similar design of hood and bodywork. The primary difference is the MP15’s standard Blomberg B trucks. == Development == Switchers up to the SW1500 had been restricted to AAR type A switcher or Flexicoil lightweight trucks, both with a wheelbase. In 1973 60 special order Mexico-only SW1504s were built on a slightly longer frame, allowing EMD’s standard Blomberg B trucks, with a wheelbase, to be used. In EMD's eyes (among others) this made the new locomotive a road switcher rather than a pure switcher, since it was capable of transition and road speeds up to or so. The new model MP15DC designation thus meant Multi-Purpose locomotive, 1500 hp, DC generator. Originally the locomotive was simply designated the MP15; the arrival of the alternator/rectifier MP15AC in 1975 changed the name. With the success of the MP15, there was a demand for a model with an advanced AC drive system. The MP15AC replaced the MP15DC’s DC generator with an alternator producing AC power which is converted to DC for the traction motors with a silicon rectifier. The MP15AC is longer than an MP15DC, the extra space being needed for the rectifier equipment. The alternator-rectifier combination is more reliable than a generator, and this equipment became the standard for new diesel-electric locomotive designs. The MP15AC is easily distinguished from the DC models. Instead of the front-mounted radiator intake and belt-driven fan used on all previous EMD switchers, these have intakes on the lower forward nose sides and electric fans. Side intakes allowed the unit to take in cooler air, and the electric fans improved a serious reliability issue found in its earlier DC sisters. 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「EMD MP15DC」の詳細全文を読む スポンサード リンク
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