Newbie variac question

[JerzeeDevil]

Hi Everyone!

I plan to use a multimeter to measure the output from a variac. The input is 120 volts and I want 110 volts out. Should I expect a constant 110 volt reading? Will it fluctuate?

 

[Beetle]

If the Variac is in good condition it should be rock-steady. I'd guess that with 120 volts input it should provide output anywhere from about 150 down to close to zero.

 

[W5LZ]

The stability of the output voltage depends entirely on the stability of the input voltage. A 'variac' is just a variable transformer and will act like one. If you operate it close to it's maximum ratings (voltage and amps) then it will also produce some variations in it's output. But the biggy is how stable and constant the input is.
- 'Doc

 

[hookedon6]

good answers on the voltage REGULATION,...... but,, why do you want exactly 110 Vac?

if that is a "hard" criteia, consider using a good regulated UPS.

BTW, 110 Vac is usually 115 - 117 Vac, jus depends on what you use to measure it with

 

[Captain Kilowatt]

good answers on the voltage REGULATION,...... but,, why do you want exactly 110 Vac?

if that is a "hard" criteia, consider using a good regulated UPS.

BTW, 110 Vac is usually 115 - 117 Vac, jus depends on what you use to measure it with

Not sure about where you live but here the 110 volt line is 120 volts normally. It used to be 110/220 years ago and then it was 115/230 but is now standardized at 120/240.My guess is he may have some older gear that was designed when 110 volts was really 110 volts or less. Some old tube gear that was meant for 110 volts does not like the higher voltage we generally have today as the filaments run hotter and some capacitors are running at or above their voltage ratings. My home has about 125 volts on the "110 volt" lines which is quite common.The pole pig is located at the end of my driveway which serves my house and one house each side of me. The volts are a bit higher than the normal 120 volts because of the long secondary run to the neighbors however the 125 volts I am getting is rock stable and just at the high end of the acceptable limits of proper voltage. I have had a few pieces of tube gear that actually had the plate supply voltage exceed the filter cap ratings because of this.

 

[hookedon6]

Not sure about where you live but here the 110 volt line is 120 volts normally...

agreed, here in the hills of Tn my power is up and down all over the scale.

in FL it is rock steady

it was just the way the OP refered to 110 Vac, kinda threw me.

I almost went into a true power, apparent power, RMS voltage vs peak voltage,..... ect type answer

perhaps I read too much into the question