AC and DC refer to alternating current and direct current respectively. AC is typically supplied by the power companies and, in the U. S., will be alternating sinusoidally at 60 hertz (Hz), at about ±120, ±240, or ±480 volts (V) peak. Many other countries supply AC at 50 Hz. Single-phase AC provides a single sinusoid varying with time, and 3-phase AC provides three sinusoids at 1200 phase angles. DC current is constant with time, supplied from generators or battery sources and is most often used in vehicles, such as ships, automobiles, aircraft, etc. Batteries are made in multiples of 1.5 V, with 6, 12, and 24 V being the most common. Electric motors are also classed by their rated power as shown in Table 2-5. Both AC and DC motors are designed to provide continuous rotary output. While they can be stalled momentarily against a load, they can not tolerate
a full-current, zero-velocity stall for more than a few minutes without overheating
AC and DC refer to alternating current and direct current respectively. AC is typically supplied by the power companies and, in the U. S., will be alternating sinusoidally at 60 hertz (Hz), at about ±120, ±240, or ±480 volts (V) peak. Many other countries supply AC at 50 Hz. Single-phase AC provides a single sinusoid varying with time, and 3-phase AC provides three sinusoids at 1200 phase angles. DC current is constant with time, supplied from generators or battery sources and is most often used in vehicles, such as ships, automobiles, aircraft, etc. Batteries are made in multiples of 1.5 V, with 6, 12, and 24 V being the most common. Electric motors are also classed by their rated power as shown in Table 2-5. Both AC and DC motors are designed to provide continuous rotary output. While they can be stalled momentarily against a load, they can not toleratea full-current, zero-velocity stall for more than a few minutes without overheating
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