Author Question: How to get the power rating in Watts from a label? (Read 2021 times)

j_sun · **on:** Jun 25, 2013

Okay so my Science homework is like this Energy Audit thing and I've got the formulas to calculate stuff if I input the power rating in watts for each appliance anyway my computer says 50hz 5Amps 240v (Australian Outlet Voltage by the way) so I can I can calculate the power rating in watts from this

Millan · **Reply #1 on:** Jun 25, 2013

W = V * A. So W = 5 * 240

Jones · **Reply #2 on:** Jun 25, 2013

You can calculate Wattage by multiplying voltage and current (5*240=1200W). You mention that its a project on energy. Just an fyi energy is wattage over a time period. So you would need to multiply that over the time the computer is on. Most cases it's in kWh so watch your units...

TI · **Reply #3 on:** Jun 25, 2013

Equal 1200 watts maximum power can be used from each outlet.

TI · **Reply #4 on:** Jun 25, 2013

The formula for watts (not VA) is W=(240 *5)*Power Factor.

The power factor of a computer is less than 1, so the watts will be less than 1200.

Your computer is rated at 1200 VA (volt-amperes).

TexMav