[Test-Equipment] Vibrotest 218 B

[Eric Lemmon]

Ooops!  I meant to type "Jim" but my klutsy fingers typed "Jeff".  My bad!

73, Eric Lemmon WB6FLY
 

-----Original Message-----
From: test-equipment-bounces at mailman.qth.net
[mailto:test-equipment-bounces at mailman.qth.net] On Behalf Of Eric Lemmon
Sent: Thursday, November 01, 2007 7:50 PM
To: 'Discussion of Electronic Test Equipment'
Subject: RE: [Test-Equipment] Vibrotest 218 B

Jeff,

The Vibrotest Model 218 was likely the very first mass-produced insulation
resistance tester.  It operated on two large 1.5 VDC dry cells, and used a
vibrator to chop the DC into AC that was then stepped up to a high voltage
and rectified.  This voltage was then connected to a cable to measure the
quality of the insulation base upon the leakage current displayed on a large
microammeter.  You may be able to get a manual or tech data from the
manufacturer here:

<www.asresearch.com/>

Associated Research made a number of offbeat instruments that used a
vibrator in the power supply, just like the radio in my 1950 Ford.  I happen
to have a Vibroground Model 263 that works just fine for performing standard
fall-of-potential ground resistance checks, using either a three-point or
four-point connection scheme.  A similar but current model tester with the
same sensitivity and accuracy from AEMC or Biddle is priced around $2,000!

73, Eric Lemmon WB6FLY


-----Original Message-----
From: test-equipment-bounces at mailman.qth.net
[mailto:test-equipment-bounces at mailman.qth.net] On Behalf Of Jim Cundiff
Sent: Thursday, November 01, 2007 4:32 PM
To: test-equipment at mailman.qth.net
Subject: [Test-Equipment] Vibrotest 218 B

Hello All,
    I am new to this list so please forgive me if this has been covered. 
I just acquired the subject instrument. The label reads:

Vibrotest
U.S. Navy type B
Model 218
Ser No 2182319   Date 5-8-45
100 Megohms - 600 Volts
Associated Research, Inc.
Chicago, ILL

Stenciled on the back is:   MARS    AFA3GSW

The unit has space for two batteries. Can someone please tell me the 
voltage of the batteries and/or provide a copy of the manual? Thank you 
in advance for any help you can provide.

In His service,
Jim Cundiff KB3GFC
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