Page 25: of Maritime Reporter Magazine (May 15, 1973)

Pacific NW Section Discusses

Shipboard Electrical Systems

Taking part in the meeting, left to right: Jock Keene, discusser; William R. Lapper, author of the paper; Lewis

Reinders, discusser, and Robert Cullen, charman, British

Columbia Area, Pacific Northwest Section of SNAME.

An especially deep and thorough coverage of the subject "Shipboard Electrical System

Design" was presented on March 29 to mem- bers and guests of the Pacific Northwest Sec- tion of The Society of Naval Architects and

Marine Engineers in Vancouver, British Co- lumbia, by William R. Lapper, W.R. Lapper & Associates.

The author commenced by stressing that proper attention must be paid to electrical and electronic systems in the design stage. Of prime importance is the integration of the gen- eration, distribution and utilization systems, and this is only possible by viewing the whole electrical and electronic picture while assessing the actual operating conditions.

Mr. Lapper then presented his format for listing all electrical requirements. The factors that emerge from his analysis are the estimated electrical load in kilowatts under varying op- erational conditions, as well as horsepower ratings of the larger electric motors.

In 1963, the author obtained approval from the Canadian Steamship Inspection Services for the feedback of electrical power fr"om the emergency generator to the main switchboard, providing certain conditions were met. The first of these conditions was that the feedback of power would be limited to the capability of the emergency generator set and secondly, feedback of power would be interrupted in the event of the start-up of any of the emergency pumps normally powered from the emergency switchboard. These requirements were met by introducing two additional circuit breakers, labeled by the author as a "Tie-breaker" and a "Feedback-breaker," with suitable interlocks so that when one was closed the other would open.

In 1967, Mr. Lapper convinced the Canadian

Steamship Inspection Service of the advantages of eliminating a central bank of transformers and instead, providing a series of small three- phase transformers, each mounted in its own sub-distribution panel, with a fixed number of double-pole, molded case, air circuit breakers.

Two of the several advantages of this system are minimum of disruption should one trans- former burn out, and reduction in feeder cable size due to the kVA demand being supplied at 440 volts.

The author feels shipyard personnel must appreciate the importance of integrating the electrical and electronic shipboard systems at the design stage in order that equipment sup- pliers may be able to bid on the most economi- cal basis to provide a satisfactory solution to the problems. He also hopes that suppliers accept suggestions for modification and im- provement which will result in more compact and better integrated installations.

Discussers were Jack Keene, Electrical In- spector, Department of Transport, and Lewis

Reinders, Lewis & Associates Engineering,

Ltd., firm of consulting engineers.

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May 15, 1973 27