Modern diesel-electric drilling rig equipment

A modern Diesel-electric powered drilling equipment for drilling oil wells consists of several internal combustion engines driving d-c generators, which supply adjustable voltage power to the several d-c motors driving the various motions. This paper gives a description of the functions performed by the draw works, mud pumps, rotary table, and coring reel, and a typical arrangement of apparatus or elementary power diagram showing the main d-c circuits with the arrangement of drill-hoist contactors and manual transfer switches. In addition, there are related the general scheme of operation, strictly from the driller's point of view, without the details of how these functions are accomplished; the operating principles of the electrohydraulic governor that make this scheme of operation possible; as well as the various control features provided by the amplidyne excitation of the main generators. The electrohydraulic governor, a war development, is applied for the first time to Diesel-electric drilling rig equipment. This governor gives to the engines a degree of protection never before attained, by preventing the engine from being overloaded. The governor also permits running the engines at the lowest speeds consistent with the desired rig motion and not at full rated speed at all times as in the past. The electrohydraulic governor provides for engine paralleling without the driller having to pay any attention to the engine throttles. The merits of a-c versus d-c auxiliary drives are pointed out, and separate engine-driven auxiliary a-c generators are recommended instead of the usual practice of driving auxiliary d-c generators from the main engines. This gives a saving in first cost of auxiliaries conservatively estimated at 25 per cent, as well as gains in simplicity, sturdiness, and less weight.