Voltage and Voltage Range
Voltage or "Rated Voltage" refers to the nominal voltage at which the units will most closely follow the stated specifications. (e.g. 220VAC.) "Voltage Range" indicates the minimum and maximum voltages at which the fan will operate. (e.g. 160VAC ~ 240VAC for a 220VAC fan.) It should be noted that in most cases if you run a fan at lower than nominal voltage the fan will slow down and if you run at a higher than nominal voltage the fan will speed up.
AC & DC Voltage
Standard AC voltages in North America are 110, 115, 120V (standard household, outlet current) and 220, 230, 240V (standard household, large appliance current) Note that 110, 115 and 120V are considered equivalent for most applications as are 220, 230 and 240V. Power delivered from a public grid varies from place to place. In rural areas you may measure 110VAC from a wall outlet with a volt meter while in a city you may be able to measure AC power at levels as high as 127VAC.
There is no need to be concerned about these minor differences however as most electrical devices operate over a voltage range with varying efficiency levels. Other custom AC voltages are available by (200 piece) special order. The range of custom AC voltages is approximately 12VAC ~ 480VAC.
Standard DC voltages are 5, 12, 24 and 48VDC. Custom DC voltages are available by special order.