The disorder results from overproduction of collagen, a naturally occurring protein found in the skin. It is unknown what causes this overproduction of collagen to occur but the immune system is believed to play a significant role. Morphea is not contagious or passed down in families.
A typical US household voltage is 120/240 V, 60 hz, single phase. There is a tolerance and the actual measured voltage is rarely exactly 120 volts. A common reading at my house is 117 volts. Industrial motors are made and rated in multiples of 115V (115, 230, 460, and 550Vac) for use on line voltages in multiples of 120 V (120, 240, 480, and 600 Vac).
The AC output voltage of a power inverter device is often the same as the standard power line voltage, such as household 120 VAC or 240 VAC. This allows the inverter to power numerous types of equipment designed to operate off the standard line power.