[Hallicrafters] vibrator how it works

[Edward B Richards]

Hi Glen;

Just to be a nit-picker, I believe most vibrators vibrate at 120 cps not
60 cps. There are special vibrators that do vibrate at 60 CPS but it
takes a heavy armature to vibrate that slow. Also, connecting a 60 CPS
source to the transformer can cause problems as the transformer was
designed for 120 CPS. Please don't shoot me.

73, Ed K6UUZ

On Sat, 14 Apr 2007 17:08:00 -0700 (PDT) Glen Zook <gzook at yahoo.com>
writes:
> Basically a vibrator reverses the direction of a DC
> voltage thus simulating an AC voltage as applied to a
> power transformer.  Often this is done using a
> transformer with a center tapped primary with the tap
> going to ground.  The vibrator applies the DC voltage
> (doesn't matter if the source is positive ground or
> negative ground) to first one side of the primary
> winding and then to the other side.  Most vibrators
> reverse the voltage around 120 times per second which
> approximates 60 Hz AC.
> 
> The voltage from the secondary of the transformer is
> basically AC and has to be rectified to produce DC for
> the unit to operate.
> 
> The recification can be accomplished either
> electronically (i.e. with some sort of vacuum tube or
> solid-state) or mechanically by separate contacts
> within the vibrator that are 180 degrees out of phase
> with the input voltage.  Vibrators which mechanically
> "rectify" the high voltage are called "syncronous"
> vibrators.
> 
> Back when most VHF FM units available to amateur radio
> operators were obsolete commercial FM mobiles it was
> very common to unplug the vibrator and to insert
> either 6.3 VAC or 12.6 VAC from a filament transformer
> (depending on whether the unit was designed for 6 volt
> or 12 volt DC operation) to use the unit as a base
> station.
> 
> Glen, K9STH
> 
> 
> --- "Duane Fischer, W8DBF" <dfischer at usol.com> wrote:
> 
> For those among the hundreds upon hundreds of us who
> populate this fascinating list, perhaps one of you
> tech dudes would explain to those who do not know what
> a radio vibrator does and exactly how it does it?
> Thank  you.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Glen, K9STH
> 
> Website:  http://k9sth.com
> 
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