Meters, used in WS19 and WS 62

While working on the restore of various WS19's, one notices the various types of meters that have been used. Not a surprise if one realises that so many factories built these sets and the demand for parts must have been enormous. Meters were often not built by the radio factories but by specialized companies, like Simpson, Weston, Triplett and many more.

Supplemental information on meters and indications was kindly supplied by Chris Suslowicz, G8KGS:
"FG" symbol on many WW2 meters means "First Grade" (I think the "X4" suffix is a wartime modifier indicating a further relaxation of the accuracy limits due to the need for quantity over quality.)

The British Standard 49 (1909) and BS 89(1954) were the standards for direct-reading analogue electrical instruments.

BS49 had classes "Sub Standard", "First Grade" and "Second Grade" (and possibly Third Grade!) when it was issued in 1909. There were various subsequent amendment sheets to it.

BS89 changed "Sub Standard" (S.S.) to "Precision" (Pr), "First Grade" to "Industrial" (In) and dropped "Second Grade" altogether when it came out in 1954.

"Sub Standard" or "Precision" is basically laboratory bench meters with calibration certificates against a national standard.

"First Grade" or "Industrial" is mainly for panel-mounted meters.

If a meter doesn't have one of those markings, it's effectively "Indication Only" and not to be relied on for an accurate value reading."

For those of you who need physical sizes of the meters, I made this PDF-file, to download. You're welcome.

	One thing all WS19 meters have in common: they carry on the scale the text: "W.S. No. 19 VOLTMETER" The scale reads 15 Volt and 600 volt. Indications on the scale: 0.5 M.A.F.S. - 0,5 milli Amps Full Scale USE EXT. RES. - use external resistor for shunting purposes moving coil - the magnetic system F.G.X.4 - "First Grade" X4 is related to the accuracy/calibration 1942 - obvious No. F - type or serial number of the meter W.S. No. 19 VOLTMETER - obvious RES.= 500 Ohm - internal resistance of the meter Click photo to enlarge.

	Component number: ZA3155/84 Serial number: 459079 This type of meter is seen in British builds. It was attached to the front with a clamping ring. A sort of seal can be seen attached to the bezel.



	This meter was made by Weston. Model: 506 It was mounted using a clamping ring. Click photo to enlarge.





	This model carries no further information, except for the factory logo on the back: Simpson. It was the common type on most Canadian built WS19's. Click photo to enlarge.



	The stamp says: "CALIBRATED FOR USE ON STEEL PANEL". And the stock number: SC1154A.

	This is a very good looking WS 62 Voltmeter. The silver scale reads 15 Volt and 600 volt and shows the Broad Arrow. It is mounted by means of a clamping ring. Indications on the scale: 0.5 mA. F.S. - 0,5 milli Amps Full Scale USE EXT. RES. - use external resistor for shunting purposes F.Ltd - the factory that built it: Ferranti. ZA25649 - the part catalogue number moving coil - the magnetic system F.G.X.4 - "First Grade" X4 is related to the accuracy/calibration 1945 - obvious (The WS62 was built at the end of 1945 and first deployed as Allied troops were already fighting in Germany) (B) - factory sign? No. F - type or serial number of the meter M.T. No.4T - not a clue - Magnet Type? VOLTMETER - obvious RES.= 500 Ohm - internal resistance of the meter 7TA - not a clue Click photo to enlarge.

	Serial number: 11601 Information, coming from Chris: "B.S. 89 was the British Standard for "Indicating Ammeters, Voltmeters, etc." and the accuracy grades (marked on the scale) during WW2 were "S.S" for Sub-Standard (i.e. calibrated directly against a "standard" ammeter and used for laboratory work), "F.G." for First Grade, and "S.G." for Second Grade.[1] (Second Grade was fairly horrible and eventually disappeared.) Post-WW2 the names changed, and "SS" (Sub-Standard) became "Pr" (Precision), while "F.G." became "In" (Industrial). I'm not sure what the "X4" meant, but probably a relaxation of the actual error limits due to the needs of wartime production. There were other suffix letters used, such as 'M' or 'G' for Metal or Glass bearings used due to the shortage of jewels for the pivots." Thanks, Chris.

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