# Measuring volt-amperes

F

#### Fred C.

Jan 1, 1970
0
I have a spec for a furnace accessory that requires 2VA (volt-amperes)
minimum from transformer (120VAC to 24VAC.) I can measure the 24
volts, but how do I determine the volt-amperes? Many thanks.

L

#### Louis Bybee

Jan 1, 1970
0
Fred C. said:
I have a spec for a furnace accessory that requires 2VA (volt-amperes)
minimum from transformer (120VAC to 24VAC.) I can measure the 24
volts, but how do I determine the volt-amperes? Many thanks.

The VA, or Volt Amp requirement has already been determined for you. The 2
VA rating required by the furnace accessory you have is well below the
capacity of most small transformers of the type usually used for furnace
control devices. Assuming your device requires 24 VAC (quite common with
heating systems) you should be able to purchase an appropriate transformer
that mounts to an electrical box from an outlet supplying the heating trade,
electrical supply outlet, etc.

A simplified calculation of your situation would yield:
VA/Volts= 2/24=.083 amps. Not exactly a high current device.

Not knowing your skill level, or knowledge of such things, I would urge you
to consult an electrical, or HVAC technician before actually engaging in
your project. Quite often heating control devices (depending on the furnace
type) are utilized to switch line level 120v or greater) voltage.

Louis--
*********************************************
Remove the two fish in address to respond

R

#### Rich Grise

Jan 1, 1970
0
I have a spec for a furnace accessory that requires 2VA (volt-amperes)
minimum from transformer (120VAC to 24VAC.) I can measure the 24
volts, but how do I determine the volt-amperes? Many thanks.

The transformer itself should have come with a specification that tells
the maximum volt-amps it can provide.

Good Luck!
Rich

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