Maintaining electrical power quality within automated systems
As covered in a previous Digi-Key article on the specifics of dirty utility power, there are half a dozen power-quality issues (including voltage surges, outages, frequency instabilities, and noise) that can arise from fluctuations in the local utility power grid. Further complicating matters is that variations can also originate from within each piece of electrically powered automation equipment. Fortunately, components abound to address such electric- power consistency issues. These power supplies and other power
machinery from having a negative impact on the local utility power grid. The two main types of power- quality problems arising from within equipment are noise and harmonic disturbances. Electrical noise in electrical power refers to high-frequency voltage variations. High frequency is relative — but always indicates frequencies considerably higher than the system ac frequency. Viewed in the time domain, an ac current should appear as a smooth sinusoidal wave. Noise makes the wave ragged and rough.
By Lisa Eitel Contributed By DigiKey's North American Editors
components make machinery perform its best and prevent
Figure 1: This PULS CP-Series single-phase power supply mounts to DIN rail so common in industrial automation. Features include high immunity to transients and power surges as well as low electromagnetic emission, a DC-OK relay contact, 20% output power reserves (covered later in this article), and minimal inrush current surge. The specially coated power supply also executes active power factor correction or PFC functions. (Image source: EE World)
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