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Compensation of the magnetic field created by an aluminum-framed ship rolling in the earth's field : trials on HMCS "Comox" (AMc 146)

From National Research Council Canada

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DOIResolve DOI: https://doi.org/10.4224/40003387
AuthorSearch for: 1; Search for: 1
Affiliation
  1. National Research Council Canada
SponsorSearch for: National Research Council Canada
FormatText, Technical Report
Physical description48 p.
Abstract
Eddy-current compensating systems with two types of detector were investigated during rolling trials on the aluminum-framed minesweeper HMCS "Comox" One type of detector, consisting of a mast-head pickup coil, gave a signal proportional to the emf's generated in the ship's framework by flux cutting of the earth's magnetic field. The other type, consisting of a shunt with a current transformer, attached to the ship's deck, gave a signal proportional to the current flowing in the framework. The mast-head type was found to be preferable. The experimental equipment was capable of reducing the ship's field to 1/3 at 19 feet and to 1/4 at 24 feet and greater depths, for roll angles of ± 15°. However, at maximum roll (± 25 °) this equipment could not supply the required compensating currents without serious waveform distortion. Results indicate that the phase-advance requirement in the amplifiers arises from the tilt effect. A single-time-constant phase-advance network has the required frequency characteristics to compensate this effect.
Publication date
PublisherNational Research Council Canada. Radio and Electrical Engineering Division
Series
  • Report (National Research Council Canada. Electrical Engineering and Radio Branch. ERA), no. ERA-312 (October 1957).
LanguageEnglish
Peer reviewedNo
NRC numberNRCC 35402
NRC-INMS-3092
NPARC number8898661
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Record identifiercefff49c-4863-4d79-83ce-02ef742e6849
Record created2009-04-22
Record modified2025-12-18
Date modified: