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A power box (USA) or feeder pillar (UK) is a cabinet for electrical equipment, mounted in the street and controlling the electrical supply to a number of houses in a neighborhood. A power box is simply a layman's term for a transformer , cutout enclosure, or other enclosure used in conjunction with underground electrical distribution.
In direct current (DC) circuits, this product is equal to the real power, measured in watts. [3] The volt-ampere is dimensionally equivalent to the watt: in SI units, 1 V⋅A = 1 W. VA rating is most used for generators and transformers, and other power handling equipment, where loads may be reactive (inductive or capacitive).
At low values of power factor, more apparent power needs to be transferred to get the same real power. To get 1 kW of real power at 0.2 power factor, 5 kVA of apparent power needs to be transferred (1 kW ÷ 0.2 = 5 kVA). This apparent power must be produced and transmitted to the load and is subject to losses in the production and transmission ...
power rating is specified in terms of apparent power (KVA or MVA), since the exact power factor will be determined by the external factors; [5] power factor (PF) is the nominal power factor for other ratings; usually PF = 0.8; [5] insulation class (B, F, H) for the primary coil. Typical value is F, although older generators might use class B; [5]
Most UPS below one kilovolt-ampere (1 kVA) are of the line-interactive or standby variety which are usually less expensive. For large power units, dynamic uninterruptible power supplies (DUPS) are sometimes used. A synchronous motor/alternator is connected on the mains via a choke. Energy is stored in a flywheel. When the mains power fails, an ...
(source: Alexandra von Meier Power System Lectures, UC Berkeley) E 1 and E 2 are the voltages of sides 1 and 2 in volts. N 1 is the number of turns the coil on side 1 has. N 2 is the number of turns the coil on side 2 has. V base1 and V base2 are the base voltages on sides 1 and 2.
A pole-mounted three-phase distribution transformer. Low-voltage feeders distributing power to households are placed below the transformer. A low-voltage network or secondary network is a part of electric power distribution which carries electric energy from distribution transformers to electricity meters of end customers.
The maximum power measured is the nominal power of the module in Watts. Colloquially, this is also written as "W p"; this format is colloquial as it is outside the standard by adding suffixes to standardized units. The nominal power divided by the light power that falls on the module (area x 1000 W/m 2) is the efficiency.