Isolation transformer outlet voltage

8/16/2010 7:42:45 PMVinny

Greetings,
I just received a used Isolation transformer (Tenma 72-545); I have never owned or used one before that I can remember. It has 2 outlets, one isolated at 1.5Amps and one not isolated at 5 Amps. The wall outlet measures 125 Volts, the non-isolated outlet on the transformer measures 125 Volts but the isolated outlet measures 135 Volts. As to my inexperience I would like to know if it is normal to be 10 Volts off? Can it damage any radios or test equipment? I did notice the difference with my worklight.
Thank you,
Vin

8/17/2010 8:16:22 AMEdd

Sir Vinny. . . . .

I'm thinking that this is your mentioned Tenma unit:

That "new" unit . . . definitely seems to be having that "old design " (50 years past), look to it.

And I don't particularly see the placement of the second pass thru, unisolated outlet.

But relevant to that 135AC output, . . . that sounds about right.
All you have to do is reach up and rotate the BIG knob on the top from being in its its max CW position, rotating CCW to decrease the AC output voltage accordingly.

(While you are at it, take your left hand and wrap your thumb and fingers over the top of the unit and see just how far you can carry the unit, before it ends up on the top your foot. . . heavy huhhhhh?)

73's de Edd

:Greetings,
:I just received a used Isolation transformer (Tenma 72-545); I have never owned or used one before that I can remember. It has 2 outlets, one isolated at 1.5Amps and one not isolated at 5 Amps. The wall outlet measures 125 Volts, the non-isolated outlet on the transformer measures 125 Volts but the isolated outlet measures 135 Volts. As to my inexperience I would like to know if it is normal to be 10 Volts off? Can it damage any radios or test equipment? I did notice the difference with my worklight.
:Thank you,
:Vin
:
:

8/17/2010 8:56:41 AMLewis L

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:Sir Vinny. . . . .
:
:
:I'm thinking that this is your mentioned Tenma unit:
:
:
:

:
:
:
:
:
:That "new" unit . . . definitely seems to be having that "old design " (50 years past), look to it.
:
:
:And I don't particularly see the placement of the second pass thru, unisolated outlet.
:
:
:But relevant to that 135AC output, . . . that sounds about right.
:All you have to do is reach up and rotate the BIG knob on the top from being in its its max CW position, rotating CCW to decrease the AC output voltage accordingly.
:
:
:(While you are at it, take your left hand and wrap your thumb and fingers over the top of the unit and see just how far you can carry the unit, before it ends up on the top your foot. . . heavy huhhhhh?)
:
:
:
:
:
:
:73's de Edd
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:

:

:
:

Sir Edd:
I must, as much as I hate to, disagree with you on the picture of the "isolation transformer". That picture looks to me like a plain old Variac with no isolation to it.
Lewis
:
:
::Greetings,
::I just received a used Isolation transformer (Tenma 72-545); I have never owned or used one before that I can remember. It has 2 outlets, one isolated at 1.5Amps and one not isolated at 5 Amps. The wall outlet measures 125 Volts, the non-isolated outlet on the transformer measures 125 Volts but the isolated outlet measures 135 Volts. As to my inexperience I would like to know if it is normal to be 10 Volts off? Can it damage any radios or test equipment? I did notice the difference with my worklight.
::Thank you,
::Vin
::
::
:

8/17/2010 9:17:57 AMLewis L

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::::

::
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::

::
::
::
::
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::
::
::Sir Vinny. . . . .
::
::
::I'm thinking that this is your mentioned Tenma unit:
::
::
::

::
::
::
::
::
::That "new" unit . . . definitely seems to be having that "old design " (50 years past), look to it.
::
::
::And I don't particularly see the placement of the second pass thru, unisolated outlet.
::
::
::But relevant to that 135AC output, . . . that sounds about right.
::All you have to do is reach up and rotate the BIG knob on the top from being in its its max CW position, rotating CCW to decrease the AC output voltage accordingly.
::
::
::(While you are at it, take your left hand and wrap your thumb and fingers over the top of the unit and see just how far you can carry the unit, before it ends up on the top your foot. . . heavy huhhhhh?)
::
::
::
::
::
::
::73's de Edd
::
::
::

::

::
::
:
:Sir Edd:
:I must, as much as I hate to, disagree with you on the picture of the "isolation transformer". That picture looks to me like a plain old Variac with no isolation to it.
:Lewis
::
::
:::Greetings,
:::I just received a used Isolation transformer (Tenma 72-545); I have never owned or used one before that I can remember. It has 2 outlets, one isolated at 1.5Amps and one not isolated at 5 Amps. The wall outlet measures 125 Volts, the non-isolated outlet on the transformer measures 125 Volts but the isolated outlet measures 135 Volts. As to my inexperience I would like to know if it is normal to be 10 Volts off? Can it damage any radios or test equipment? I did notice the difference with my worklight.
:::Thank you,
:::Vin
:::
:::
::
:
A thousand most humble apologies, Sir Edd. After a more careful perusal of the internet, I must concur that you are absolutely correct. If Sir Vin will just adjust knob to 115 Volts, he should be extremely pleased with his purchase. A Variac and an isolation transformer in one package. Niiiiize machine, you got there, Vin! Good going.

Lewis

8/17/2010 9:21:55 AMEdd

Sir . . . . . Lewis

Hmmmmmmm . . . oh tay . . . now, as for that photo, since it was the only immediate deee-piction that I found on Tenma products of that nature, with the over the water site needing . . . " most honnable" . . . graphics plug in.
Since it doesn't quite have the popularity of a Hoolet Plastered . . . Tek or B&K following . . . . but I'll bet cha' that the BIG knob on the top is correct.

Vinny . .. aas per your isolation aspect confirmation. . . just low ohms scale out . . . between the incoming AC cords two prongs and the AC output socket connections on the unit.

73's de Edd

::
::

::::

::

::
::
::
::
::
::
::
::
::
::
::Sir Vinny. . . . .
::
::
::I'm thinking that this is your mentioned Tenma unit:
::
::
::
::
::
::
::
::
::That "new" unit . . . definitely seems to be having that "old design " (50 years past), look to it.
::
::
::And I don't particularly see the placement of the second pass thru, unisolated outlet.
::
::
::But relevant to that 135AC output, . . . that sounds about right.
::All you have to do is reach up and rotate the BIG knob on the top from being in its its max CW position, rotating CCW to decrease the AC output voltage accordingly.
::
::
::(While you are at it, take your left hand and wrap your thumb and fingers over the top of the unit and see just how far you can carry the unit, before it ends up on the top your foot. . . heavy huhhhhh?)
::
::
::
::
::
::
::73's de Edd
::
::
::

::

::
::
:

:Sir Edd:
:I must, as much as I hate to, disagree with you on the picture of the "isolation transformer". That picture looks to me like a plain old Variac with no isolation to it.
:Lewis
::

::
::
:::Greetings,
:::I just received a used Isolation transformer (Tenma 72-545); I have never owned or used one before that I can remember. It has 2 outlets, one isolated at 1.5Amps and one not isolated at 5 Amps. The wall outlet measures 125 Volts, the non-isolated outlet on the transformer measures 125 Volts but the isolated outlet measures 135 Volts. As to my inexperience I would like to know if it is normal to be 10 Volts off? Can it damage any radios or test equipment? I did notice the difference with my worklight.
:::Thank you,
:::Vin
:::
:::
::
:

8/17/2010 9:43:43 AMLewis L

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:
:

:
:
:
:
:
:
:
:Sir . . . . . Lewis
:
:
:Hmmmmmmm . . . oh tay . . . now, as for that photo, since it was the only immediate deee-piction that I found on Tenma products of that nature, with the over the water site needing . . . " most honnable" . . . graphics plug in.
:Since it doesn't quite have the popularity of a Hoolet Plastered . . . Tek or B&K following . . . . but I'll bet cha' that the BIG knob on the top is correct.

However, Sir Edd, that 135 Volts output did ring a bell , I finally figgered out that is the max Variac output Voltage when one is wired to do so. Heats up my soldering iron faster, for sure.
Lewis
PS Mailing some more dial cord today. It is actually some sort of cable tie cord, used on engines and other places of high vibrationm but is sure works good as dial cord.
LL

:
:
:
:Vinny . .. aas per your isolation aspect confirmation. . . just low ohms scale out . . . between the incoming AC cords two prongs and the AC output socket connections on the unit.
:
:
:
:
:
:
:
:73's de Edd
:
:
:

:
:
:
:
:
:
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:::
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:::
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:::
:::Sir Vinny. . . . .
:::
:::
:::I'm thinking that this is your mentioned Tenma unit:
:::
:::
:::

:::
:::
:::
:::
:::
:::That "new" unit . . . definitely seems to be having that "old design " (50 years past), look to it.
:::
:::
:::And I don't particularly see the placement of the second pass thru, unisolated outlet.
:::
:::
:::But relevant to that 135AC output, . . . that sounds about right.
:::All you have to do is reach up and rotate the BIG knob on the top from being in its its max CW position, rotating CCW to decrease the AC output voltage accordingly.
:::
:::
:::(While you are at it, take your left hand and wrap your thumb and fingers over the top of the unit and see just how far you can carry the unit, before it ends up on the top your foot. . . heavy huhhhhh?)
:::
:::
:::
:::
:::
:::
:::73's de Edd
:::
:::
:::

:::

:::
:::
::
:
:
:
::Sir Edd:
::I must, as much as I hate to, disagree with you on the picture of the "isolation transformer". That picture looks to me like a plain old Variac with no isolation to it.
::Lewis
:::
:
:
:::
:::
::::Greetings,
::::I just received a used Isolation transformer (Tenma 72-545); I have never owned or used one before that I can remember. It has 2 outlets, one isolated at 1.5Amps and one not isolated at 5 Amps. The wall outlet measures 125 Volts, the non-isolated outlet on the transformer measures 125 Volts but the isolated outlet measures 135 Volts. As to my inexperience I would like to know if it is normal to be 10 Volts off? Can it damage any radios or test equipment? I did notice the difference with my worklight.
::::Thank you,
::::Vin
::::
::::
:::
::
:

8/17/2010 10:53:39 AMEdd

AAhhhhhh Sooooooo . . . . Most Honnable . . . Mistah Loo-Weesss . . .

NOW. . .In fully kicking into my X-ray vision mode (with an additional measure of ESP ALSO being thrown in):

I am clearly seeing the height profile being needed for the Variac aspect at the very top of the unit.

Now irregardless of the "old camp" design aspect and external appearance of the unit . . . firmly resting there . . mounted just BELOW the units top Variac is a "new" 22nd century toroid transformer, providing its isolative primary and secondary windings aspect.(Along with high power density within a small packaging profile.)

It do be sittin' thar' . . . jes likes one big 'oles . . . Krispy Creme donuts . . . (on STEEE-roids.)

Since we see the input AC cord being over to the right bottom front, with its associated twist in Line Fuse, seems like if one goes to the left, just past that sub Emico quality, round AC ammeter, one could have that pass thru AC unisolated plug being mounted over there, on the adjunct side plate.

(Pee Ess . . . Vinny probably won't be back to read this until he completes his doctoral internships 88 straight / solid hours on, to then, be able to get his meager 8 hours off.)( KILLERS ! )

73's de Edd

::
::

::
::
::
::
::
::
::
::
::
::
::Sir . . . . . Lewis
::
::
::Hmmmmmmm . . . oh tay . . . now, as for that photo, since it was the only immediate deee-piction that I found on Tenma products of that nature, with the over the water site needing . . . " most honnable" . . . graphics plug in.
::Since it doesn't quite have the popularity of a Hoolet Plastered . . . Tek or B&K following . . . . but I'll bet cha' that the BIG knob on the top is correct.
:

:
:However, Sir Edd, that 135 Volts output did ring a bell , I finally figgered out that is the max Variac output Voltage when one is wired to do so. Heats up my soldering iron faster, for sure.
:Lewis
:PS Mailing some more dial cord today. It is actually some sort of cable tie cord, used on engines and other places of high vibrationm but is sure works good as dial cord.

:
::
::
::
::Vinny . .. as per your isolation aspect confirmation. . . just low ohms scale out . . . between the incoming AC cords two prongs and the AC output socket connections on the unit.
::
::
::
::
::
::
::
::73's de Edd
::
::
::

::

::
::
::
::
::
::
::
::
::
::::
::::

::::::::

::::

::::
::::
::::
::::
::::
::::
::::
::::
::::
::::
::::Sir Vinny. . . . .
::::
::::
::::I'm thinking that this is your mentioned Tenma unit:
::::
::::
::::
::::
::::
::::
::::
::::
::::That "new" unit . . . definitely seems to be having that "old design " (50 years past), look to it.
::::
::::
::::And I don't particularly see the placement of the second pass thru, unisolated outlet.
::::
::::
::::But relevant to that 135AC output, . . . that sounds about right.
::::All you have to do is reach up and rotate the BIG knob on the top from being in its its max CW position, rotating CCW to decrease the AC output voltage accordingly.
::::
::::
::::(While you are at it, take your left hand and wrap your thumb and fingers over the top of the unit and see just how far you can carry the unit, before it ends up on the top your foot. . . heavy huhhhhh?)
::::
::::
::::
::::
::::
::::
::::73's de Edd
::::
::::
::::

::::

::::
::::
:::
::
::
::
:::Sir Edd:
:::I must, as much as I hate to, disagree with you on the picture of the "isolation transformer". That picture looks to me like a plain old Variac with no isolation to it.
:::Lewis
::::
::
::
::::
::::
:::::Greetings,
:::::I just received a used Isolation transformer (Tenma 72-545); I have never owned or used one before that I can remember. It has 2 outlets, one isolated at 1.5Amps and one not isolated at 5 Amps. The wall outlet measures 125 Volts, the non-isolated outlet on the transformer measures 125 Volts but the isolated outlet measures 135 Volts. As to my inexperience I would like to know if it is normal to be 10 Volts off? Can it damage any radios or test equipment? I did notice the difference with my worklight.
:::::Thank you,
:::::Vin
:::::
:::::
::::
:::
::
:

8/17/2010 2:27:50 PMVinny

Greetings, thank you for your responses, I am still undecided in sending this one back.

Today I tested again and primary was 124.4 and the isolated secondary was 133.6.

The side label says 120 input and 120 output.

I am concerned that if my work light burned brighter at a higher voltage (60 watt bulb), then a radio at 30 watts may have a problem. Also considering that some probably were designed schematically at about 117 volts.

It would have been nice if the suspected one were actual.

Dr. Edd, just a day off today, but you are right a lot of work and not enough time. KILLERS!

Vinny A.

8/17/2010 4:02:41 PMEdd

Sir . . . . . .Vinny

HEYYYYYY . . . . you are absolutely correct, with that unit being COMPLETELY different from anything in the Tenma line, that I could readily find any pictures of.

Sort of resembles a narrow RCA Isovolt series, which has a rotary switch for its tap offs which give 5 volt AC
variances between the selected voltage steps.

Now if you were to plug a 100 watt lamp load into the isolated output plug and then find that high of a voltage level, that unit just might not be your cup ofd tea, unless, you got it so cheep, that you could additionally get a cheep Variac to use in conjunction with it for the voltage variance adjustment aspect.

73's de Edd

:
:
:Greetings, thank you for your responses, I am still undecided in sending this one back.
:
:
:Today I tested again and primary was 124.4 and the isolated secondary was 133.6.
:
:The side label says 120 input and 120 output.
:
:I am concerned that if my work light burned brighter at a higher voltage (60 watt bulb), then a radio at 30 watts may have a problem. Also considering that some probably were designed schematically at about 117 volts.
:
:It would have been nice if the suspected one were actual.
:
:Dr. Edd, just a day off today, but you are right a lot of work and not enough time. KILLERS!
:
:Vinny A.
:
:

8/17/2010 6:52:49 PMPeter G. Balazsy

Here's another picture of a Tenma 72-545:

8/17/2010 10:33:41 AMNorm Leal

Hi Vin

A transformer output voltage will be high until load is applied. Nothing wrong reading 135 volts without a load.

Norm

8/19/2010 1:33:38 PMVinny

Thank you for all your opinions.
I decided to send it back for a full refund. I am going to get a new one, no sense in taking a chance with any type of protection device.
For the money I like the one Bob Z mentioned in a previous thread and also the one Dr. Edd has mentioned in this thread, a bit to expensive however.

Vinny A.