Peakstrøm

Peakstrøm is a term used in electrical engineering to describe the maximum instantaneous current drawn by an electrical circuit or device during operation. It is distinct from average or RMS current and is a critical parameter for assessing component stress, insulation, and protection strategies.

Origin and usage: The term combines 'peak' with 'strøm' (Norwegian/Danish for current), reflecting its prevalence in Nordic technical literature, though the concept is universal.

Measurement and interpretation: Peak current is defined as the maximum value of i(t) over time. For a sinusoidal current with rms Irms, the peak Ip = sqrt(2) * Irms. For non-sinusoidal waveforms, Ip is determined from the waveform or measured with an oscilloscope or peak-reading instruments. The peak value is related to the crest factor, which is the ratio Ip/Irms.

Applications and significance: Peak current ratings are used in selecting fuses and circuit breakers, and in the design of power supplies, motor controllers, battery charging systems, surge protection, and transformer insulation. Peak currents during switching, inrush, or transient events can dominate thermal and mechanical stress, influencing reliability and safety margins.

Limitations and considerations: The peak value can vary with load, switching behavior, source impedance, and waveform shape. Transient peaks may exceed nominal ratings, so designs typically incorporate margins and evaluate crest-factor implications to ensure protection devices and conductors tolerate short-duration peaks.

See also: crest factor, inrush current, surge current, RMS current.