The AM Forum
March 29, 2024, 11:37:47 AM *
Welcome, Guest. Please login or register.

Login with username, password and session length
 
   Home   Help Calendar Links Staff List Gallery Login Register  
Pages: [1]   Go Down
  Print  
Author Topic: 800Hz panel meter question  (Read 1576 times)
0 Members and 1 Guest are viewing this topic.
Opcom
Patrick J. / KD5OEI
Contributing
Member
*
Offline Offline

Posts: 8308



WWW
« on: July 21, 2020, 01:14:11 PM »

I have a nice pair of panel meters, 0-150VAC 800Hz. They do indicate correctly on 60Hz, but there is too much current or something. The needle almost 'sticks;' when energized but is free when un-energized, that is, tilting the meter right-left-right it swings normally. It's not ruined, but I'm trying to figure out how to use it even if I have to modify something like the rectifier or multiplier etc. As far as I can tell it's a moving coil movement, not a vane. I have assumed it's aDC movement, but have not opened them.I thought I knew alot about panel meters, but apparently not. I would like to use them to show both sides of the 240V line voltage.
Logged

Radio Candelstein - Flagship Station of the NRK Radio Network.
KA3EKH
Member

Offline Offline

Posts: 773



WWW
« Reply #1 on: July 22, 2020, 11:06:00 AM »

Maybe meters from a TBW or GP series WW2 transmitter. They used 800 Hz power supplies because they required smaller transformers and filters in the power supplies and they also used the raw 800 Hz to feed the suppressor of the 803 PA tube to develop A2 or AM CW.
The TBW had a gasoline powered 800 Hz generator and cannot imagine what that sounded like in operation. I had a TBW that I built up a regular AC power supply that I use to run and somehow think it had a meter that had two scales one for input voltage and a second scale for 0 to 15 volts that was used for setting the filament voltage of the PA tube, may a want to check because your 150 volt meter may just be a 15 volt meter?

Logged
Opcom
Patrick J. / KD5OEI
Contributing
Member
*
Offline Offline

Posts: 8308



WWW
« Reply #2 on: August 08, 2020, 02:03:37 PM »

Maybe the mechanism is similar. These have just the one scale and are what looks like a standard GE AC Volts panel meter from the 50's tp 70's, mostly square/rectangular but with rounded corners. The size is perhaps 4" across. The usual very small markings on the bottom of the scale may have a part number, but I recall seeing 800~ there. They are a similar style to the image attached.

I noticed there is a very slight vibration of the pointer on 60Hz. I've see 400Hz ac meters indicate well on 60Hz but more current was drawn.

Since it's an AC meter with a moving coil, it could either be the permanent magnet stator type using a rectifier,  or the electromagnetic stator type which does not need a rectifier if those are/were still in use. Maybe I could take note of the meter's resistance and try a little DC current.

I can't tell more without taking it apart and I'd rather not for fear of breaking it.


* large GE meter ~4 inch.jpg (24.04 KB, 563x465 - viewed 206 times.)
Logged

Radio Candelstein - Flagship Station of the NRK Radio Network.
Pages: [1]   Go Up
  Print  
 
Jump to:  

AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
 AMfone © 2001-2015
Powered by SMF 1.1.21 | SMF © 2015, Simple Machines
Page created in 0.07 seconds with 19 queries.