# How to calculate the power requirements of a fan motor? [closed]

I bought a fan from the USA to use in Europe. The fan's specifications states the following:

Requires a grounded electrical supply line of 120 volts AC, 60 Hz, 15 amp circuit.

Here we use a 220V, 50-60Hz supply. I've managed to find a step down transformer at a local electrical store that is a 220V-110V transformer for home use. They have a two models — 50VA and 100VA.

Which one would I need to power my fan? Is the 50VA, sufficient?

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VA is the apparent power. So, assuming there is no reactive power, your power requirement is $V*I=120*15=1800 W$ or $VA$. Now, when you double your voltage, your power requirement will not change, but the current needed will change. A 100VA transformer will give you $\dfrac{100 VA}{220 V}=0.45 A$. You need 8.2A at least without calculating the losses. That fan will not spin very fast. What you need is a 1.8kVA step-down transformer. – abdullah kahraman Jun 19 '12 at 8:05
By the way, what kind of fan is that?! – abdullah kahraman Jun 19 '12 at 8:08
Hi Abdullah, Here's the spec sheet.: fanimation.com/support/download_pdf.html?media_id=3478 – Mridang Agarwalla Jun 19 '12 at 8:32
Supporting consumer electronics is off topic for our site. – Kortuk Jun 19 '12 at 11:11

## closed as off topic by Kortuk♦Jun 19 '12 at 11:11

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@Mridang - Voltage $\times$ Amperage gives you VA, which is an indication for power, which is given in watt. (In resistive loads they are the same.) For a home fan like the one we're talking about the package will probably mention the power (watt), not current or VA. – stevenvh Jun 19 '12 at 9:34