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Message 29597 in TECH.WW

From: G8MNY
Date: Tue, 08 Sep 26 07:03:00 Z
Newsgroups: TECH.WW
Subject: Variacs
Message-ID: <4479_GB7CIP>
Path: N2NOV|VE2PKT|VE2HOM|N9PMO|CX2SA|GB7CIP

R:260908/0710z @:N2NOV.#RICH.NY.USA.NOAM $:4479_GB7CIP
R:260908/0710Z 17493@VE2PKT.#TRV.QC.CAN.NOAM LinBPQ6.0.25
R:260908/0709Z 7982@VE2HOM.#LAN.QC.CAN.NOAM LinBPQ6.0.25
R:260908/0709Z 9185@N9PMO.N9PMO.#SEWI.WI.USA.NA BPQ6.0.25
R:260908/0709Z @:CX2SA.SAL.URY.SOAM #:4036 [Salto] FBB7.00e $:4479_GB7CIP
R:260908/0703Z @:GB7CIP.#32.GBR.EURO #:4479 [Caterham Surrey GBR] $:4479_GB7CIP

From: G8MNY@GB7CIP.#32.GBR.EURO
To  : TECH@WW

By G8MNY                                      (New Dec 07)
(8 Bit ASCII graphics use code page 437 or 850, Terminal Font)

Varaic is a traded name of The General Radio Co. for a variable tapped toroid
mains auto transformer (non isolating) usually with up to 17% overvoltage.

      260o__             Ratings are normally in amps. But this can be
      240o__||) fuse     confusing as the laminate core will have a power

 fuse 220   ||)          when the core has the maximum work to do of half the
            ||)          output rating, as half the output current flows
  INPUT     ||) OUTPUT   through the top section and half comes up from the
      -10o__||)          lower. However using a few % from the top or bottom



                         mains fuse and a 3A fast blow on the output should do.

      Wiper         _     Turns














                      knob

Bad arcing can damage the brush and windings. Do check the brush and spring out
if you have arcing. Insulation damage can cause fires as a shorted turn has
almost infinite current available.

With toroidals the winding are exposed on the outside and variacs even more so
if the bare windings are not fully encased,


See my buls "70-260V Mains Auto Transformer", "Constant Voltage Transformers",
"Maplin Mains Meter 2000MU-UK", "Portable Appliance Testing" & also "Mains
Power Protection".


Why Don't U send an interesting bul?

73 de John G8MNY @ GB7CIP




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