Joe, I have the above listed models. My opinion of the 540B is that it requires a lot of work. Reading the manual, it suggests swapping cables for repeatability to get a good reading.
It originally shipped with a mercury cell for the galvanometer so you may get a D sized dead/leaking battery. It also has a large Ni-Cd pack for operation since it is not recommended for use while plugged in. There is no proper battery charging circuit so you will have to monitor the charge time. Also, there appears to have been two versions of the plug-in unit. They are either A54-1 or A54-2. I cannot tell you the difference between the two. I think that the A54-2 had better input protection. Hopefully you can get one with a good thermal element that has not been blown out. There is a procedure on EEVblog for determining if the thermal element is not damaged. I found a link a few months ago where Transmille was using the input port for the A55 thermal converters as an output line. They connected the output to different 8.5 digit multimeters to characterize an AC source. My 8506A's are very nice. They are spec'd to 1Mhz and make a good second 7.5 digit DC meter too. Unfortunately, you cannot do AC current measurements without using external shunts like the A45 series. I have two different A55 thermal converters, but they have not been thoroughly tested. I would recommend getting the Ballantine 1395A/B thermal converters as they appear to be better supported by cal labs. I think Ballantine still sells them and will do repairs and calibrations. My other favorite is the Fluke 8920A. I think it is a good meter. It's 3.5 digit display is augmented by a DC analog output that you can connect to an external meter. The 8920A is recommended for calibrating the 5100B series wideband output. Another potential AC measurement standard would be the Datron/Wavetek 4920 or 4950 reference standards. The cost to calibrate from Fluke is astronomical though. You can look up the pricing on their website to see what they charge. $3K-4K if I remember correctly. Before I sent my 3458A in for calibration, the NVRAM was changed and I performed the SCAL using my 5100B and 8920A. I was able to get the cal to pass and was very surprised when Gary Bierman told me that all tests passed during calibration. I think you should consider getting both the 8506A and 8920A. Pick up a set of shunts whenever you can get a good deal. Todd On Tue, Jul 8, 2014 at 9:46 PM, J. L. Trantham <[email protected]> wrote: > I've been thinking about adding an AC Voltage Measurement Standard to my > shop. > > > > It would appear that most of these have to do with thermal converters. > Does > anyone have any thoughts about this? > > > > I've been thinking about a Fluke 540B, 8506A, or a collection of A55 > Thermal > Converters. I have accurate DC measurement tools and DC standards. > > > > I would appreciate any thoughts. > > > > Thanks in advance. > > > > Joe > > _______________________________________________ > volt-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there. > _______________________________________________ volt-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
