[volt-nuts] Fluke 5200A AC Calibrator

[Chuck Harris]

Being as you are in the UK, land of 50Hz power mains, any false indications
on 50 Hz would likely be the result of ground loops, or coupling (inductive
or capacitive) from things hooked to your power mains, and 100Hz the result
of ripple on power supplies.

Have you checked the filter caps on all of the affected instruments?

-Chuck Harris

David C. Partridge wrote:
> Replying to my own post - but I do have highly pertinent information:
>
> I received an email from a person I know at Ametek:
>
>> As for the lower frequencies, did you try using the AC filter button?
>> I tried my (annually calibrated) 7081 on a Fluke 5720A before leaving
>> work and at 50Hz I got virtually the same reading as you, 1.00367.
>> Selecting the AC filter gave a much improved reading of 1.00002.
>> I haven't got the operating manual to hand but I seem to remember it
>> recommending using the filter at 50Hz and below.
>
> He was pretty much on the mark, though the manual recommends the filter
> be used below 1kHz!
>
> With AC filter engaged:
>
>   Frequency  Reading    Error
>   50Hz       0.999996   .0004%
>   100Hz      0.999868   .0132%<--- A little high but not bad