When dealing with supply power and motors, frequency is a predetermined factor. A basic understanding of frequency properties helps engineers and operators to understand motor frequency issues, variable frequency drives (VFDs), as well as voltage and power phase.
AC Power and Frequency
In electric circuits, the time rate of energy flow past a given point of the circuit is instantaneous power. In alternating current (AC) circuits, capacitors and inductors are energy storage elements that can result in periodic reversals of the energy flow direction. The International System of Units (SI) is the watt.
AC power is a form of electrical current that reverses direction within a determined interval. The sine wave is the standard waveform of most AC power circuits, where the amplitude is a function of the magnitude of the current flowing through the circuit. The distance between two identical points on the sine wave, the two crests at the top or two troughs at the bottom, is the wavelength. The wavelength is determined by the operating frequency, not the passing current. The period is the time between two identical points on the sine wave, which would be 16.6 milliseconds at a frequency of 60 Hz, meaning 60 cycles per second.
Frequency is the rate at which electrical current changes direction per second, defined as the number of crests of a wave that move past a given point in a specific amount of time. Frequency is measured in hertz (Hz), the most common unit of frequency, with the international unit of measure being 1 Hz = 1 cycle per second. A cycle = one complete wave of voltage or alternating current. Frequency is predetermined when dealing with supply power and motors. Typically, all power in the United States supplied to businesses and homes is at 60 Hz, with nearly all power provided to businesses and homes in the AC form.
Illinois Process Equipment, IPE, is a leading Midwest pump and process equipment supplier with deep technical knowledge of AC power, frequency, and variable speed drives.
IPE offers fully integrated pump services, including complete system design and engineering, installation and testing, field service, maintenance, and repair. We differ from other pump suppliers with our deep technical knowledge of pumping processes across a broad range of market segments. Contact us to learn more about our pumping solutions, including sine wave, sinusoidal pumps.