[TenTec] Operating voltage(s)

[Sherrill WATKINS]

I tend to agree with Mr. Mansey's observations on operating voltage.   Ohms's law and common sense indicates that if one operates on the high side that the additional voltage will cause the resistors, transistors and transformers to run hotter.  This alone will shorten the life of the equipment.   There have been several articles in ELECTRIC RADIO and the OLD TIMERS BULLETIN about the benefitts of operating old and antique vacuum tube equipment at low supply voltage from a Variac or step down transformer.   It seems that a 5 to 10% drop in the filament voltage and a 10 to 20% drop in the B+ will work wonders on greatly extending the life of boatachor equipment.   I have confirmed this as a friend of mine used to maintain the Virginia State Police statewide point to point microwave links and was one of the persons who first installed the system in the early 1960's.  At that time it was all vacuum tube operated.   He said that at some remote locatons the utility line voltage was very low, around 113vac , instead of the normal 120 vac.  The equipment stayed on all the time and in 18 years at those locations they never had to replace any vacuum tubes!!  At my house, the line voltage is very high, measured at 125. 3 vac, and I am constantly replacing burned out light bulbs. - Sherrill W. k4own

>>> "William Mansey" <WA2PVK@prodigy.net> 09/14/00 09:36PM >>>

My opinion on the subject is that it is NOT good to operate equipment at
EITHER "end" of the recommended voltage range.  Too low a supply voltage is
as potentially harmful as too much.  Ohm's law states that (among other
things) that Power equals current times voltage.  If a piece of equipment
tries to maintain the same amount of power and the voltage is reduced - - -
then the current would have to increase to make up the difference.  Many
types of electronic equipment have circuits requiring different voltages
also.  This means voltage regulators are used.  Voltage extremes can give
regulators a workout.  My suggestion is to stay comfortably within the
specified voltage range!  Any potential gains in power out are not worth the
risks involved.  This is, of course, just my opinion.  I do tend to be
careful where the risks out weigh the gains!  NOT to mention the expense of
fixing or replacing something!


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