The actual range of frequency relays produced by DOLD has been extended by 2 additional devices. Both models detect under or over frequency in AC voltage systems. The varimeter IK9143 needs no auxiliary supply and is suitable to monitor frequency in 50/60Hz systems like generator sets and local power generation. The inexpensive module has a setting range of ± 10% and an adjustable hysteresis.

The more powerful varimeter IL9837 in-cludes an adjustable setting range of 1…300Hz and a wide input voltage range of 10…500V. Therefore this frequency relay is suitable to monitor the output fre-quency of inverters. Adjustable hysteresis and LED indicators for auxiliary voltage, measuring voltage and state of output contact are standard features on this de-vice.

The enclosures dimensions are 17.5 and 35x90x59 mm.