Digital Phasemeter - what is it?
 

Hello, everyone. At a recent hamfest, I spotted an Acton Laboratories model 330A "Digital Phasemeter". I mainly bought it for the nixie tubes it uses for a display (four, plus one for the "-" negative symbol), but I'd at least like to find out what it's used for, and if I might have any sort of use for it before I go about stripping it of parts. Unfortunately, information on this sort of piece of test equipment seems to be fairly thin on the ground, unless it's better known by a different name. Any ideas? Thanks in advance!
-Adam

can you post a picture of the front and back or a list of connections and controls?

I think I dealt with something like this long ago. I'm guessing it takes two sine wave inputs of the same frequency and displays or allows you to measure their relative phase. I don't know what frequency range this covers - could be only audio or video.

Edit: it might be only for power frequencies. Trying to fire up some long-dormant neurons here.

Possibly used as a readout with a resolver or synchro type position transducer.

Yes that's what it is. The frequency range is unknown but those seldom went above audio. Some exceptions - there were some rf ones but they weren't digital.

Very expensive when new. Not terribly useful.

I have an antique digital voltmeter (1965?), five digits, AC and DC, covers the audio range, and the specs say it's 0.01% on DC. It hasn't been calibrated in years but it too uses Nixie tubes for a readout. It is in three units, the readout, the power supply, and the AC converter. It works fine but I'd really like it to find another home.

Thanks for all the replies. I haven't gotten the pictures out of my digital camera yet, but I can list the controls. On the front panel, along the top, are controls for OFF-STDBY-ON, and NORM-ADD 180º. Along the bottom are sets of binding posts for REFERENCE and SIGNAL inputs(?), each with a LEVEL control with 2-20V and 2-200V settings. The SIGNAL side also has an unmarked red pushbutton nearby.

On the rear panel is an asset tag dating to 1962, and two pots with locking shafts marked SET 0º and SET 180º, each with a small pushbutton, and a set of unmarked binding posts which were obviously added later.

One cool thing about the front panel is that the nixie tube display window can be tilted up or down, in addition to being centered. Not sure how much this thing cost, but it probably wasn't too cheap in its day.
-Adam

The panel features are pretty much self explanatory. The rear pots are calibrations; you hold the button and and watch the meter as you adjust.

My old digital voltmeter also has a display tilt feature.

It's used to display the phase relationship between two sinusoidal waveforms, usually the outputs of synchros or resolvers, as someone mentioned.

The reference input is the signal measured from - that is, the signal input will be 0-359 degrees leading or lagging the reference. We used them in the Navy quite extensively - they saw heavy use in autopilot/auto stabilization (avionics) equipment testing. North Atlantic was a manufacturer of one phasemeter we used, and they also make phase angle voltmeters as well.

A Phase meter has to work with varying voltages and frequencies, like 60Hz, 400Hz (airvborne), 115VAC, and 26VAC systems, the latter being common in aviation.

The one you have sounds like one that we had installed in our shipboard jet engine test cells, used to remotely measure the angle (deflection) of inlet actuators. You'd compare the other performance factors to the phasemeter reading to determine the optimum settings for an jet engine "run" on the cell
Useful item to those who need it - I'd personally save it from the scrap pile, as the new LCD based meters lack the "cool" factor of nixies.

Cheers,

My HP 203A function generator has four outputs. The phase between the first pair and the second pair is adjustable from 0 to 360 degrees.