► First select the suitable input AC voltage (115VAC, 230VAC, 400VAC, or 3x 400VAC) for your unregulated 28VDC power supply unit.
► Then buy unregulated 28VDC power supply units with the output current that is appropriate for you, with top-hat rail or for wall mounting, or power supply units with an extremely high degree of protection.
With these unregulated (filtered / smoothed) 28V power supplies from FEAS, a secondary AC voltage is generated by means of a transformer and rectified via a rectifier circuit. The resulting pulsating DC voltage is then smoothed with filter capacitors. The DC voltage of the unregulated 28V power supply units is approx. 1.42 times higher than the effective secondary AC voltage. Depending on the input AC voltage and DC load, the output voltage may vary slightly. The design of the unregulated 28V power supplies is robust and limited to the essentials. These sieve-smoothed 28V power supplies are sufficient for driving valves, relays, contactors and Manget switches and for most PLC controls.