Murata's self-powered LED meter displays AC line frequency



DMR20 round, miniature digital panel frequency monitor

Murata announced the third generation of the DMR20 series of round, miniature digital panel frequency monitors from Murata Power Solutions. Designed to measure and display AC mains frequencies in the range of 45 to 65 Hertz, over an input voltage of 85 to 264 VAC, the monitor is suitable for mounting in an industry-standard “oiltight” 30 and 30.5 mm / 1.2 inch round panel cutout.

The DMR20-1-FM-R-C frequency monitor is a self-powered, 2-wire meter that does not require any additional external power sources. Equipped with a quartz crystal controlled microcontroller-based timing circuitry, this monitor is a companion product to Murata’s AC voltmeter, model number DMR20-1-ACV-R-C.

The meter has a display resolution of one hundredth of a Hertz (0.01Hz) from 45 to 65 Hertz, making it an attractive replacement for outdated analog frequency-meters and meaning that no additional components or separate power supply is required for the unit.

The unit features a rugged housing with seamless construction on all sides, providing protection to IP67 / NEMA 6 specifications for dust, dirt and moisture. Typical applications include use in industrial and consumer backup generators, marine instrument panels, power distribution units (PDUs), off-grid power generation, portable generators, utility test sets and as a replacement for old analog “needle-style” frequency meters.

The DMR20 can operate from – 25 to + 60 degrees C.