(19)

(11)

EP 0 412 097 A1

(12)

(43) Date of publication: 13.02.1991 Bulletin 1991/07 (21) Application number: 89905156.0 (22) Date of filing: 21.04.1989

(51) International Patent Classification (IPC):  G01R 11/ 24( . ) G01R 33/ 07( . ) G01R 33/ 025( . ) (86) International application number: PCT/GB1989/000426 (87) International publication number: WO 1989/010570 (02.11.1989 Gazette 1989/26)

(84) Designated Contracting States: AT BE CH DE FR GB IT LI LU NL SE (30) Priority: 21.04.1988 GB 19880009381 28.06.1988 GB 19880015391 21.10.1988 GB 19880024657 17.11.1988 GB 19880026948 (71) Applicant: OMEGA ELECTRIC LIMITED Mitcheldean, Gloucestershire GL17 0EB (GB)	(72) Inventors: WILKS, Andrew, John Highclare Highview Way Lydney, Gloucestershire (GB) WILLIAMS, Peter, Geoffrey Flaxley Mill Gloucestershire GL17 0EB (GB) (74) Representative: James, Michael John Gwynne, et al  Wynne-Jones, Lainé & James 22, Rodney Road Cheltenham Gloucestershire GL50 1JJ Cheltenham Gloucestershire GL50 1JJ (GB)