I have a project for which I use a wall wart with 18VAC (not DC) output. Is
it safe to leave such an unloaded transformer plugged in for periods of
time? If not, what would be a good solution other than plugging the unit in
and out. Thanks in advance for all information.

Al KA5JGV

"Al" wrote in message
...
I have a project for which I use a wall wart with 18VAC (not DC) output.
Is
it safe to leave such an unloaded transformer plugged in for periods of
time? If not, what would be a good solution other than plugging the unit
in
and out. Thanks in advance for all information.

Al KA5JGV

It is fine to leave it plugged in. If it is UL listed it should be as safe
as the millions of them in service.
Unloaded they should not develop as much heat as a loaded one.

Al wrote:

I have a project for which I use a wall wart with 18VAC (not DC) output. Is
it safe to leave such an unloaded transformer plugged in for periods of
time?

Leave it plugged in for awhile and then feel of it.
If it is warm or hot, it's a poor design, and there
are some of those out there.
--
73, Cecil http://www.qsl.net/w5dxp


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Al, KA5GV wrote:
"If not, what would be a good solution other than plugging the unit in
and out?"

Overheating is a fire hazard eliminated by a fuse or circuit breaker
which limits current to a safe value.

The power circuits in your house may be protected with 15-amp breakers.
The wiring is then safely chosen to carry 15 amps with no danger that
the wires will overheat.

15 amps in your wall wart may set it on fire with no help from your
load-center. This can be prevented with a fuse or breaker on the wall
wart by itself which limits the current to less than it takes to set the
device on fire.

Best regards, Richard Harrison, KB5WZI

Thank you for your replies. Like it or not, I feel most comfortable if I
unplug the unit.
Al

"Al" wrote in message
...
Thank you for your replies. Like it or not, I feel most comfortable if I
unplug the unit.
Al

Al

Do you unplug your TV? It is always on, drawing some current . Then
there is the electric clock. The list could go on and on in most
households.

That is -- If your mind is already made up, why ask a question about
wallwarts on an antenna news group

Jerry

Jerry, I posted to this group because it is one of the most knowledgeable
and dependable.

The TV, clock, etc. are not unloaded like the transformer I asked about. I
don't know if it is safe to leave an unloaded transformer plugged in, so I
asked. I placed a resistive load across the transformer to keep a slight
load across it, but not being sure if this is OK or not, I decided to unplug
the transformer for safety.

Al


"Jerry Martes" wrote in message
news:sE0Ud.48125$uc.8371@trnddc03...
Do you unplug your TV? It is always on, drawing some current . Then
there is the electric clock. The list could go on and on in most
households.

That is -- If your mind is already made up, why ask a question about
wallwarts on an antenna news group

Jerry

The TV, clock, etc. are not unloaded like the transformer I asked about. I
don't know if it is safe to leave an unloaded transformer plugged in, so I
asked. I placed a resistive load across the transformer to keep a slight
load across it, but not being sure if this is OK or not, I decided to
unplug
the transformer for safety.



Look at it this way, there are millions of unloaded door bell transformers
in the US.
The only time they are activated (loaded) is for about 2 seconds when
someone rings the bell. Mine usually rings once a week for pizza and a
couple of times for visitors.

The transformers will draw a slight ammount of current so you may save a
dollar or two each year if you unplug it.

Wealthy, energy-rich Americans, Europeans and Japanese have no idea that a
cent a day can save the lives of millions of starving and waterless people
on this small, over-populated Earth of ours.

Or should we rely on Aids, influenza virus, malaria, American deployed
weapons of mass-destruction, hurricanes, earthquakes, floods and suicide
bombers to solve the problem?

Perhaps the 6000-year old, modernised, Chinese and Babylonian wisdoms should
be allowed to predominate in the media over the piffle George and Tony said
last week.

Reg Edwards wrote:
Wealthy, energy-rich Americans, Europeans and Japanese have no idea that a
cent a day can save the lives of millions of starving and waterless people
on this small, over-populated Earth of ours. . .

But our wise commentator doesn't have any idea how many lives can be
saved for the price of a year's wine consumption?

Roy Lewallen, W7EL