Why do I need a Variac?

[ctwo]

For a long time I've wanted a variac, but I'm not sure why as I have survived decades without one. Do any of you have a practical use for one? I know they are good for powering up old tube equipment. I do have a Collins R-388/URR receiver and maybe I will make a hot knife some day. I'm sure it's not a good idea to use one on a single phase drill press, but I don't many other good ideas. That's all I can think of... My grandfather had a smallish one with fine wire that I was supposed to get, but the junk man got there first.

[armscor 1]

I used variacs to calibrate thermal overloads by varying the current through the heating element and magnetic overloads.
A total necessity for setting up switchgear.

[tornitore45]

I have two a 100VA and a 500VA I have needed to used them about 4 times in the last 15 years and do not recall the specific.
If you want one get one, on the other hand you may spend the next decades without needing one.
Sometime a simple dimmer can do the job, like when converting an espresso maker tank into a Cerro Bend melting pot.

[Lew Hartswick]

Where are you ? I have a couple of the medium power ones in the shed. I had two big ones (one a true Variac [rtm] and the other that other Co. ) 240 /120 at 25 A that I sold just last year. They have been in the shed for the 23 years since I retired.
...lew...

[Bentworker]

They are good for hot knives, pickup / dropout tests on AC coil voltage and current relays. Pickle lightbulbs (google it).

[Russ Hanscom]

A simple router solid state speed control, good for 25 amps from Rockler, might work just as well unless you really have your heart set on a Variac. Pretty sure mine has not been used in 20+ years.

[Steggy]

I have a Variac that has been in storage since back when Bill Clinton was president. One of these days I might put it up for sale. Of course, about five minutes after I sell it I'll discover I need it to test something.

[John Hasler]

Triac chopper speed controls are not useful for testing inductive loads such as AC relay coils or for determining the correct AC operating voltage for a device unless it is purely resistive and you have a true RMS voltmeter.

[Conrad_R_Hoffman]

It's a downhill slope. If you get a Variac, you'll then find you need a voltmeter and an ammeter and maybe an isolation transformer. I use one in the electronics lab for powering up old and suspect equipment, but how often do you do that? For hot knives and such, you really need that isolation transformer to avoid death.

[ctwo]

I am (mentally) looking through all of my loose transformers wondering if any of of them could be purposed as an isolation transformer. Coincidentally or not, the thought of touching a hot knife came to mind.

[John Hasler]

You can use two identical transformers back to back as an isolation transformer.

[SteveM]

People use them for slowly powering up old tube equipment so as to not damage anything.

Eddie Van Halen used to run his amp on one set to a slightly lower voltage than line voltage.

I have several. Last time I used one was similar to Mauro's use; I needed to control a mini crock pot to melt chocolate.

Steve