Rating Plate
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A rating plate on a machine carries information about its operational limits. The plate frequently contains the names of the machine and its manufacturer, so the rating plate is often called a
name plate A nameplate identifies and displays a person or product's name. Nameplates are usually shaped as rectangles but are also seen in other shapes, sometimes taking on the shape of someone's written name. Nameplates primarily serve an informat ...
(hence the term "
nameplate capacity Nameplate capacity, also known as the rated capacity, nominal capacity, installed capacity, maximum effect or gross capacity, For an
electric machine Electricity is the set of physical phenomena associated with the presence and motion of matter possessing an electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by ...
, the
power rating In electrical engineering and mechanical engineering, the power rating of equipment is the highest power input allowed to flow through particular equipment. According to the particular discipline, the term ''power'' may refer to electrical or ...
is the number on its rating plate and corresponds to a maximum
electric load An electrical load is an electrical component or portion of a circuit that consumes (active) electric power, such as electrical appliances and lights inside the home. The term may also refer to the power consumed by a circuit. This is opposed ...
it can carry. There is a distinction between the ''continuous rating'' (for generators, continuous maximum rating or CMR), at which the machine can be operational without a time limit and short-term rating that can only be used for a specified amount of time.


Generators

A typical electrical generator rating plate contains the following parameters: * ''power rating'' is specified in terms of
apparent power In an electric circuit, instantaneous power is the time rate of flow of energy past a given point of the circuit. In alternating current circuits, energy storage elements such as inductors and capacitors may result in periodic reversals of the d ...
(KVA or MVA), since the exact
power factor In electrical engineering, the power factor of an AC power system is defined as the ratio of the ''real power'' absorbed by the electrical load, load to the ''apparent power'' flowing in the circuit. Real power is the average of the instantaneou ...
will be determined by the external factors; * ''power factor'' (PF) is the nominal power factor for other ratings; usually PF = 0.8; * '' insulation class'' (B, F, H) for the primary coil. Typical value is F, although older generators might use class B; * ''type of enclosure'' (
IP code The IP code or International Protection code indicates how well a device is protected against water and dust. It is defined by the International Electrotechnical Commission (IEC) under the international standard IEC 60529 which classifies ...
); * rated voltage can be either line to line (" line voltage") or phase to neutral (" phase voltage"); * rated current is derived from the rated power and voltage: = \frac ; * ''
line frequency The utility frequency, (power) line frequency (American English) or mains frequency (British English) is the nominal frequency of the oscillations of alternating current (AC) in a wide area synchronous grid transmitted from a power station to t ...
'' (50 Hz or 60 Hz) and
rotational speed Rotational frequency, also known as rotational speed or rate of rotation (symbols ''ν'', lowercase Greek nu, and also ''n''), is the frequency of rotation of an object around an axis. Its SI unit is the reciprocal seconds (s−1); other com ...
of the
prime mover Prime mover may refer to: Philosophy *Unmoved mover, a concept in Aristotle's writings Engineering * Prime mover (engine or motor), a machine that converts various other forms of energy (chemical, electrical, fluid pressure/flow, etc.) into ener ...
in
RPM Revolutions per minute (abbreviated rpm, RPM, rev/min, r/min, or r⋅min−1) is a unit of rotational speed (or rotational frequency) for rotating machines. One revolution per minute is equivalent to hertz. Standards ISO 80000-3:2019 def ...
; * ''connection'' ( star or delta).


See also

*
Per-unit system In the power systems analysis field of electrical engineering, a per-unit system is the expression of system quantities as fractions of a defined base unit quantity. Calculations are simplified because quantities expressed as per-unit do not cha ...


References


Sources

* Electric power systems components {{Electric-power-stub