Multimeters

[MingtheMerciless]

In my early career at Brentford Electric, who made power transformers and unusual kit for people like CERN, Cullham Laboratories, Chloride batteries, we used Beckman and Fluke meters for voltages up to 1000V AC and DC. Both meters were rated for these voltages but Beckmans were preferred by the test department as they had a nice twisty selector like the black meter above, whereas the Flukes we used were push button. Both were very accurate and usually more than enough for what we needed them for, 0.1V @ 750V DC and if we needed anything more precise and to more significant figures we had a bench set that went to about 6 decimal places.

We stopped using the Beckmans, when 23hrs into a full load heat run on a multi-megawatt Transformer Rectifier for British Rail, the meter that had been connected for the 23hrs measuring voltage output (750V DC) decided enough was enough and exploded, tripping out the protection and ruining the run which had to be repeated (using a Fluke).