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Motor–generators can convert between any combination of DC and AC voltage and phase standards. Large motor–generator sets were widely used to convert industrial amounts of power while smaller units were used to convert battery power (6, 12 or 24 V DC) to a high DC voltage, which was required to operate vacuum tube (thermionic valve) equipment.
In North America and northern South America, it is usually 120 volts, 60 hertz (Hz), but in Europe, Asia, Africa, and many other parts of the world, it is usually 230 volts, 50 Hz. [2] Aircraft often use 400 Hz power internally, so 50 Hz or 60 Hz to 400 Hz frequency conversion is needed for use in the ground power unit used to power the ...
Three variants are defined by the document: P12, P24 and P48. In addition, two additional variants (P12L and SP48) are mentioned for specialized applications. [3] [4] Most microphones now use the P48 standard (maximum available power is 240 mW). Although 12 and 48-volt systems are still in use, the standard recommends a 24-volt supply for new ...
In a battery electric vehicle, there are usually two separate DC systems. The "low voltage" DC system typically operates at 12V, and serves the same purpose as in an internal combustion engine vehicle. [10] The "high voltage" system operates at 300-400V (depending on the vehicle), and provides the power for the traction motors. [11]
In both cases, power loss is strongly dependent on the duty cycle, D. Power loss on the freewheeling diode or lower switch will be proportional to its on-time. Therefore, systems designed for low duty cycle operation will suffer from higher losses in the freewheeling diode or lower switch, and for such systems it is advantageous to consider a ...
The power transmitted is equal to the product of the current and the voltage (assuming no phase difference); that is, P t = I V . {\displaystyle P_{\rm {t}}=IV\,.} Consequently, power transmitted at a higher voltage requires less loss-producing current than for the same power at a lower voltage.
The difference between the two voltages is because charging a battery requires a delta voltage (up to 13–14 V for charging a 12 V battery). Furthermore, it is easier to do the switching on the line-voltage side of the transformer because of the lower currents on that side.
Transistor–transistor logic/CMOS (TTL) power supply: 5 V; USB: 5 V DC; PP3 battery: 9 V; Automotive battery systems use cells with 2.1 volts per cell; a "12 V" battery has six cells connected in series, which produces 12.6 V; a "24 V" battery has 12 cells connected in series, producing 25.2 V. Some antique vehicles use "6 V" 3-cell batteries ...