Fluke 332B DC Voltage Standard

Fluke 332B DC Voltage Standard

© Brooke Clarke 2016

Background
Description
Capacitor Check
Photos
Other Voltage Standards
Related
References
Links

Background

This is a purley analog voltage standard. No remote control, no IEEE-488 just front panel controls. 7 digits of precision.
0 to 1,111.1110 Volts output at up to 50 mA.
10, 100 and 1,000 Volt full scale ranges.
0.1 ppm resolution.
5 ppm stability.

When I was working at Aertech in 1990 the definition of the Volt (Wiki) changed. At that time I was building automatic test systems (past project s) that made use of the HP 3458 Digital Volt Meter. Prior to the change we already had a 3458, and after the change we received a new 3458 with a front panel sticker (black "1990 SI" on green background). Tom in the metrology lab used a DC standard that looks similar to this one as a source and we measured it's output using the two 3458s, one with the old calibration and one with the new calibration and the difference was exactly the difference between the new and old standards. Note the accuracy of this standard is no an issue, it only needs to stay the same value for a few minutes. A 9 Volt battery would probably also work.

What was that difference and is this the instrument that could display it?
An email from Frank pointed me to:
https://www.nist.gov/sites/default/files/documents/calibrations/tn1263.pdf
and
http://www.eevblog.com/forum/metrology/1000-my-%28hi%29story-of-the-weston-cell-of-the-volt-and-of-being-a-volt-nuts/

The change amounted to an increase of 9.264ppm. Since the 332B has a stability of 0.1 ppm. If it was set to exactly 10 Volts that actual voltage read by the 3458 would not be exactly 10 but . . . the difference in voltage read by the pre and post "new volt" 3458 meters would differ by 9ppm.

Prior to the 1990 change the Volt was defined based on a Standard Cell (Wiki: Clark Cell, Weston Cell), such as the Eppley Standard Cell.

Description

This is an analog instrument made with what I call Golden Age construction.

Capacitor Check

Prior to powering up the capacitors on all the pllug-in boards were checked for ESR & Capacitance and they all seem OK.

A5A1 Reference Supply
A5A2 Series Pass Driver
A5A3 Differential Amplifier
A5A4 Chopper Amp
A5A5 Aux Power Supply - note C2 & C3 are coupled by the circuitry so read high
A5A6 Current Limiter - note C11 marked but not installed, so the nearby cap is really C10
A7A1 Series Pass Element
A7A2 Pre-Regulator

Photos

Fig 1

Fig 2 The AC line cord is permentley attached.

Fig 3 Cal adjustments easly available.

Fig 4 To slide out the chassis, just open the top 4 Dzus fasteners (Wiki)
and the 2 Dzus fasteners on the rear panel and slide it out.
Fig 5 Inside of cabinet is insulating.
Fig 6 While there are a number of pull-out boards there are also
baords that are bolted onto the chassis and not easily accessable.

Fig 7 Warning about chassis being 1100 Volts above line.

Other Voltage Standards

DC Voltage References
    Malone 5 Volt Reference
    Geller SVR Voltage Reference
    Lilnear Tech LTZ1000
Mallory 303113 Voltage Reference - 8 series connected Mercury batteries with taps between all the cells. 1.35V, 2.7V &Etc to 10.80 V.

2422045 Alkaline dry cell, Ruben Samuel, App: 1945-07-10, W.W.II, Pub: 1947-06-10, - Mercury battery
2462998 Primary cell with permanganate Depolarizer, Ruben Samuel, Key Mercury battery
    RE23427 Primary cell with permanganate Depolarizer, Ruben Samuel, 1951-10-30, - reissue of 2462998
2542575 Alkaline dry cell, Ruben Samuel, 1951-02-20, - Mercury
2636062 Electrochemical cell and selfventing enclosure therefor, Colton Robert, PR Mallory and Co (Duracell), 1953-04-21, - sealing vent
2712565 Electrochemical cell, Jr Fred D Williams, 1955-07-05, - corrosion free

Digital Multimeters - Fluke
Eppley Standard Cells & Pyranometer
HP3437A System Voltmeter
HP3458_DVM HP (very accurate if it can be fixed)
Kelvin Connection Measurements & HP 34401 DMM
DC Voltage References
    Malone 5 Volt Reference
    Geller SVR Voltage Reference
    Lilnear Tech LTZ1000

References

Volt Nuts mailing list: https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts

1955740 Fastening device, William Dzus, Apr 24, 1934, 411/555, 29/436

Links

PRC68, Alphanumeric Index of Web pages, Contact, Products for Sale
Page Created 7 Dec 2016

Fig 1	Fig 2 The AC line cord is permentley attached.	Fig 3 Cal adjustments easly available.
Fig 4 To slide out the chassis, just open the top 4 Dzus fasteners (Wiki) and the 2 Dzus fasteners on the rear panel and slide it out.	Fig 5 Inside of cabinet is insulating.	Fig 6 While there are a number of pull-out boards there are also baords that are bolted onto the chassis and not easily accessable.
Fig 7 Warning about chassis being 1100 Volts above line.