To step down 12 VAC to 3 VAC, you could use a step-down transformer with a winding ratio of 4:1 between primary and secondary.
Stepping Down DC VoltageYou buy a voltage converter or power supply that takes 120 VAC as an input and provides your desired 12 VAC or 12 VDC as an output. You need to know your current requirements and size the converter or power supply to provide the required amperage.
Use a 'step down' transformer. you can make your own from a bar magnet, some copper wire and a length of adhesive tape.
Wind one piece of copper wire around the bar magnet ten times - leaving a little space between the wire as you go. Connect both ends of the wire to the power source.
Wind the second piece of wire around the magnet BETWEEN the wires of the first coil (without touching) but only wind FIVE times. Connect the ends of the smaller coil to the equipment.
Once you've got the coils wrapped correctly - secure everything with some adhesive tape.
A kw (kilowatt) is 1000 amps x volts. If you assume your one phase system has 120 volts, then divide by 120. Cheap, but close enough for most work, assume 100 volts, then each amp is a tenth of a kilowatt.
Assuming DC and resistive loads, resistance equals voltage across the load, divided by the current through it. In this case 120/10 or 12 ohms.
You get power by multiplying the amperes and the voltage. 12V, 10A dc would give the same power as 120V, 1A ac.
A three phase panel will not give you 110 and 220 volts. A three phase four wire panel will, but not at these voltages. The nearest voltages will be 120 and 208 volts. The 120 volt is the wye voltage of 208 volts. 208/1.73 = 120 volts. A single phase three wire panel will give you 110 and 220 volts.
The kVA rating will be listed on the transformer's nameplate, which is usually on the front of the transformer. The 480v to 120v is irrelevant, because many transformers with different kVA ratings convert 480 volts to 120 volts. The kVA ratings can be different and thus affect the rated current through the transformer.
The potential difference of 120 volts and 12 volts is 108 volts.
No. Watts = Volts x Amps Watts does not directly convert to volts.
12 Amps x 12 volts = 1200 watts 1200 watts / by 120 volts = 10 amps at 120 volts Answer is 10 amp hours
The voltage of 120 volts is more common that the lower voltage of 12 volts.
5000w / 120 volts = 41.66 amps P=E*I transposed to I=P/E
put double power batteries in
6 amps.
160 amps at 12v.
160 amps at 12v.
Assuming this could be done with no conversion loss a 20 watt load at 120 volts would require about 1/6 of an amp. A 7 ampere hour battery would run the load for 6 x 7 = 42 hours. However, if you actually built a circuit to up convert 12 volts DC to 120 volts AC there would be significant conversion losses.
50% of 120 volts = 50% * 120 = 0.5 * 120 = 60 volts
12 Volts DC