Looking to buy a variac and was wondering if the amperage makes a difference? I've noticed they come in various amp. ratings. Thanks for any advice.

: Looking to buy a variac and was wondering if the amperage makes a difference? I've noticed they come in various amp. ratings. Thanks for any advice.
:

It should be about three times the maximum load you will expect. Communication receivers might be around .8 amps, so you should get a 2.5 or 3 amp variac. Metering is just as important for current.
J-

: Looking to buy a variac and was wondering if the amperage makes a difference? I've noticed they come in various amp. ratings. Thanks for any advice.
:
Mike,

It is not the amps that are critical when using a variac, it is the current draw of the piece of equipment you are powering up. As you increase the voltage on the variac the current also increases that is being drawn from the equipment. This is the magic in seeing what the wattage is, most important.

Some old radios can draw as much as 100 watts, less than an amp at 120 volts on the variac load side.

My bench variac is a 150 volt 5 amp with a voltmeter. I use an amp clamp in the power circuit to measure current draw from the radios so i can calculate the wattage.

Hope this helps,

Mitch

:: Looking to buy a variac and was wondering if the amperage makes a difference? I've noticed they come in various amp. ratings. Thanks for any advice.
::
:Mike,
:
:It is not the amps that are critical when using a variac, it is the current draw of the piece of equipment you are powering up. As you increase the voltage on the variac the current also increases that is being drawn from the equipment. This is the magic in seeing what the wattage is, most important.
:
:Some old radios can draw as much as 100 watts, less than an amp at 120 volts on the variac load side.
:
:My bench variac is a 150 volt 5 amp with a voltmeter. I use an amp clamp in the power circuit to measure current draw from the radios so i can calculate the wattage.
:
:Hope this helps,
:
:Mitch
:
Yes it does thank you, I'am reworking a philco 144. and when I get ready to apply power to it I want to have a variac and volt meter in place. I asked about the amps because the ones I looked at on line the price went up with the larger amp. variacs and I did'nt want to buy more than needed. The power cosumption of radio is 70watts. Thanks again

::: Looking to buy a variac and was wondering if the amperage makes a difference? I've noticed they come in various amp. ratings. Thanks for any advice.
:::
::Mike,
::
::It is not the amps that are critical when using a variac, it is the current draw of the piece of equipment you are powering up. As you increase the voltage on the variac the current also increases that is being drawn from the equipment. This is the magic in seeing what the wattage is, most important.
::
::Some old radios can draw as much as 100 watts, less than an amp at 120 volts on the variac load side.
::
::My bench variac is a 150 volt 5 amp with a voltmeter. I use an amp clamp in the power circuit to measure current draw from the radios so i can calculate the wattage.
::
::Hope this helps,
::
::Mitch
::
:Yes it does thank you, I'am reworking a philco 144. and when I get ready to apply power to it I want to have a variac and volt meter in place. I asked about the amps because the ones I looked at on line the price went up with the larger amp. variacs and I did'nt want to buy more than needed. The power cosumption of radio is 70watts. Thanks again

Of course, you can use a 10 Amp VARIAC on a one Amp radio, but the more current they can put out, the bigger, heavier, and more expensive they are. I use a 7.5 Amp, because someone gave it to me. It is almost always more than I need, but what the heck, it was free. It usually is attached to a 150 VA isolation transformer, with a 1.5 Amp circuit breaker, so it is quite a mismatch, but I fished the parts for the isolation box out of the trash at work, once again, free. I'm either cheap or maybe smart, I have been called both, among other things.
Lewis
: