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M1BYT > TECH 15.07.05 00:19l 39 Lines 1867 Bytes #999 (0) @ WW
BID : 6B3612M1BYT
Read: GUEST OE7FMI
Subj: Re: Portable Appliance Testing
Path: DB0FHN<DB0RGB<DB0MRW<DB0WUE<DK0WUE<DB0RES<ON0AR<GB7FCR
Sent: 050714/2316Z @:GB7FCR.#16.GBR.EU #:57953 [Blackpool] FBB-7.03a $:6B3612M1
From: M1BYT@GB7FCR.#16.GBR.EU
To : TECH@WW
G8MNY Opined with considerable skill:-
> More complex testers will measure the values & have different ratings for more
> delicate & lower fuse rated items. Some testers do a high voltage flash test
> (eg 3KV) to ensure the mains circuit insulation is adequate (eg unearthed TV).
Hi John,
The above flash test would normally be used on equipment described as 'double
insulated', marked by a square box within a square box symbol. The flash test
is done between any exposed metal on the appliance and the mains lead. For
instance - testing a double insulated electric drill, you would place the
flash probe on the drills chuck, with the drill plugged into the instrument.
That would confirm that the chuck is adequately insulated from the mains and
that it could not become live.
Not sure, but I think the double refers to there being two effective
insulating barriers between any mains wiring or live parts and exposed metal
work. Insulation between the windings of the motor and the shaft plus a second
barrier in the form of nylon gearing + case before the steel chuck.
ÉÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ»
º 73 from Harry, M1BYT @ GB7FCR.#16.GBR.EU º
ÌÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ͹
º International Museums Weekend 18th+19th June 2005 º
º www.ukradioamateur.org/imw/index.html º
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º The ARC's FL/RAE courses + Newcomers Introduction º
º to amateur radio:- http://www.ukradioamateur.org/ º
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º QTH: Garforth, W. Yorks.. º Timed 23:16 º
º harry.m1byt@tiscali.co.uk º 14 Jul 05 º
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