Variac as isolation transformer?

[David N.]

Can I use my variac as an isolation transformer?

Thank,
David

--

 

[Clifford Heath]

Can I use my variac as an isolation transformer?

Almost certainly not. With very few exceptions, variacs
are auto-transformers (a single winding with a common end).

 

[John Larkin]

Can I use my variac as an isolation transformer?

No.

John

 

[Michael Black]

Can I use my variac as an isolation transformer?

No, and that isn't a design question.

You really ought to be asking yourself why you think a variac is
an isolation transformer. And start with understanding what a variac
is, and what an isolation transformer is. Then, you can answer your own
question.

Michael

 

[Donald]

Can I use my variac as an isolation transformer?

Thank,
David

http://en.wikipedia.org/wiki/Variac

Homework ??

 

[John Larkin]

http://en.wikipedia.org/wiki/Variac

Homework ??

What professor, these days, would ever have heard of a variac?

John

 

[John Popelish]

Can I use my variac as an isolation transformer?

I have seen an isolated Variac, but only one. All the rest
were a single winding that functioned like an inductive
version of a potentiometer.

 

[Joel Kolstad]

What professor, these days, would ever have heard of a variac?

The old ones who haven't quite hit retirement yet?

I know a professor who -- in his undergraduate transmission lines lab -- still
has kids using an ancient tube-based TDR with those "flared blade" style WW
II-era RF connectors on it, and I'm sure he knows what a VARIAC is.

Although he might not know the proper name of those connectors, just as I
don't. (Interesting, they do appear at ham fests every now and again, but
I haven't every seen them at a commercial trade show... hmm...)

 

[Joel Kolstad]

I have seen an isolated Variac, but only one.

I own one, and it's one of those generic Chinese-made brands that you see
advertised in, e.g., Nuts & Volts. They're only a skosh more expensive than
the traditional kind.

I haven't seen high-powered isolated VARIACs, though... mine is only something
like 300W.

 

[GregS]

The old ones who haven't quite hit retirement yet?

I know a professor who -- in his undergraduate transmission lines lab -- still
has kids using an ancient tube-based TDR with those "flared blade" style WW
II-era RF connectors on it, and I'm sure he knows what a VARIAC is.

Although he might not know the proper name of those connectors, just as I
don't. (Interesting, they do appear at ham fests every now and again, but
I haven't every seen them at a commercial trade show... hmm...)

Flared Blade? So thats what those things are called. I have a 10X 20 dB attenuator
in the middle betwee two sets of BNC adaptors. I'll call it Flared Blade to BNC
and so on. The pieces are General Radio GR874

I do have a nice Staco variac with meters and optional isolation ouput. i sometimes use
that in conjection with my series light bulb box with switches for 40, 140, and 240 watts.


greg

 

[Homer J Simpson]

The old ones who haven't quite hit retirement yet?

Anyone who has read Terman and Petit?

 

[Michael A. Terrell]

The old ones who haven't quite hit retirement yet?

I know a professor who -- in his undergraduate transmission lines lab -- still
has kids using an ancient tube-based TDR with those "flared blade" style WW
II-era RF connectors on it, and I'm sure he knows what a VARIAC is.

Although he might not know the proper name of those connectors, just as I
don't. (Interesting, they do appear at ham fests every now and again, but
I haven't every seen them at a commercial trade show... hmm...)

Are you talking about the General Radio 874 Hermaphroditic
connectors?


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[Ancient_Hacker]

Can I use my variac as an isolation transformer?

Thank,
David

--

Dunno. You should be able to figure this out by unplugging it from the
wall and using an ohmmeter from input to output.

I think the congenital "Variac" has a hard time being an isolation
transformer, as it's usually just a single winding on a toroid core,
tapped off as an autotransformer.

BUT a faint memory is that there's some other manufacturer that DOES
provide variable voltage and isolation on one core. Here's one recent
one:

http://instrumentation-central.com/Staco/PDFCutSheets/VT isolated.pdf

 

[John Larkin]

The old ones who haven't quite hit retirement yet?

I know a professor who -- in his undergraduate transmission lines lab -- still
has kids using an ancient tube-based TDR with those "flared blade" style WW
II-era RF connectors on it, and I'm sure he knows what a VARIAC is.

Tek 1S2, likely. I have a few, and they're cool.

Although he might not know the proper name of those connectors, just as I
don't. (Interesting, they do appear at ham fests every now and again, but
I haven't every seen them at a commercial trade show... hmm...)

GR874 connectors.

John

 

[Joel Kolstad]

Hi Michael,

Are you talking about the General Radio 874 Hermaphroditic
connectors?

Why yes, I think I am; thanks for the real number... I'm sure I'll forget it
within weeks, but at least now Google news will remember for me!

 

[Joel Kolstad]

Tek 1S2, likely. I have a few, and they're cool.

The students (and I) were always impressed with the nifty electrostatic paper
holder on the Tek pen plotter that it's connected to. Magic!

Since you have a 1S2... one of the blades is broken off on the signal
input/output connector. Any chance of repairing it? The connector seemed
like an integrated part of some "sampling head" kind of module inside; not
just a connector that transitioned to, e.g., a coax cable.

---Joel

 

[John Larkin]

The students (and I) were always impressed with the nifty electrostatic paper
holder on the Tek pen plotter that it's connected to. Magic!

Since you have a 1S2... one of the blades is broken off on the signal
input/output connector. Any chance of repairing it? The connector seemed
like an integrated part of some "sampling head" kind of module inside; not
just a connector that transitioned to, e.g., a coax cable.

---Joel

You'd have to take it apart, but that's not bad. The unisex connector
pin should be a standard GR part. I have a lot of old GR bits and
pieces. If you take it apart and photograph things, I bet I could find
something around here that would work. I also have several broken
1S2's, so I could donate one for parts. One working TDR is better than
two dead ones.

I started learning picosecond electronics with a 1S2 plugged into a
547. The 1S2 is a 25 ps pulse generator and a 4 GHz scope, all in one
little box.

Nowadays I'm using mostly Tek 11801 series scopes with the SD24 TDR
head, all from ebay... nice rig, very precise and quantitative,
interfacable to a PC, fairly cheap.

If you hack a 50 ohm microstrip from a piece of copperclad, and TDR
it, and run your finger along the line, people get amazed. The
equivalent sweep speed is multiples of c.


John

 

[mark]

I know a professor who -- in his undergraduate transmission lines lab --
still has kids using an ancient tube-based TDR with those "flared blade"
style WW II-era RF connectors on it, and I'm sure he knows what a VARIAC
is.

Although he might not know the proper name of those connectors, just as I
don't. (Interesting, they do appear at ham fests every now and again,
but
I haven't every seen them at a commercial trade show... hmm...)

I thought they were known as GR style connectors.

M Walter

 

[Rich Grise]

http://en.wikipedia.org/wiki/Variac

Homework ??

What professor, these days, would ever have heard of a variac?[/QUOTE]

Win Hill? ;-)

Cheers!
Rich

 

[Tim Williams]

What professor, these days, would ever have heard of a variac?

My, there's a hundred of the things scattered throughout the rather small
Physics Department at Beloit!

Bunch of tubed equipment too, for that matter. Most of it is sitting in the
basement though.

Tim