Dold Frequency Monitoring Relay, DPDT, 15 → 280V ac, DIN Rail

Detection of over- or under frequency of alternating voltage (adjustable function)
Fast reaction time by measuring duration of cycle of input frequency
Universal measuring input for AC-voltages of 15 ... 280 V as well as 30 ... 550 V
As option with measuring input for inverters
Adjustable hysteresis
Adjustable monitoring time for missing input signal at function over frequency
Response delay programmable via terminals 0 ... 100 s
Alarm storing or auto-reset programmable via terminals
Galvanic separation between measuring input, auxiliary voltage and output contacts
MH 9837 available with wide input range for auxiliary supply (AC/DC 24 ... 60 V or AC/DC 110 ... 230 V)
2 changeover contacts, closed circuit operation
Open circuit operation on request
LED indication for auxiliary voltage, measuring voltage and alarm status
MH 9837.12/008: with galvanic separated analogue output (current/ voltage) and 11 step LED chain for the actual frequency
Device available with 2 response values and separately controlled output relays for under- and over frequency see MK 9837N/500