Dold Industries Ltd

11 Hamberts Rd. Blackall Ind. Estate
South Woodham Ferrers
GB-Essex, CM3 5UW
MK 9837N/5_0

Frequency Relay

MK 9837N/5_0


Auxiliary voltage

Response value


Approvals and Markings


  • 0061295
  • MK9837N.38/500 2x5-600HZ UH=AC230V
The frequency relays MK 9837N/5_0 e.g. MH 9837/5_0 are used for frequency monitoring of AC... more

Product description

The frequency relays MK 9837N/5_0 e.g. MH 9837/5_0 are used for frequency monitoring of AC voltages. They are used for monitoring the output frequenc of frequency converters (/550) or for monitoring the rotor frequency of slip ring motors. Further area of application ist the monitoring of drives in crane systems.

Technical specifications

Measuring range max.: 600 Hz
Standard measuring range: 1,5 - 600 Hz
1- / 3-phase: 1
Output contacts: 2 x 1 C/O contacts
Width: 22,5 mm
Enclosure design: Switch cabinet
Auxiliary voltage required: Yes
Type: MK 9837N/5_0


  • Separate output signals for under and over frequency
  • Simple wiring
  • Easy handling


  • According to IEC/EN 60255-1
  • Monitoring of AC voltage for under and overfrequency, can be used also for pre-warning (monitoring of AC voltage for under or overfrequency see datasheet MK 9837N)
  • Separate relay outputs for over- or underfrequency (1 or 2 changeover contacts each)
  • Alternative usage for monitoring of a frequency window
  • Separate adjustment of response value for over- or underfrequency at 4 ranges each, 1.5 ... 200 Hz or 5 ... 600 Hz
  • Second response value for prewarning possible
  • 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
  • Programmable hysteresis of response value: 2 ... 10 %
  • Start up time delay programmable via terminals from 0 ... 50 s e.g. continuously
  • Manual or auto-reset programmable via terminals
  • Galvanic separation between measuring input, auxiliary voltage and output contacts
  • MH 9837/508: With galvanic separated analogue output (current/voltage) and 11 step LED chain for the actual frequency
  • MH 9837/5_0: With wide input range for auxiliary voltage available (AC/DC 24 ... 60 V or AC/DC 110 ... 230 V)
  • Closed circuit operation (de-energized on trip)
  • LED indication for auxiliary voltage, measuring voltage and alarm status
  • Device available with 2 contacts
    MK 9837N/5_0: 2 x 1 changeover contact
    MH 9837/5_0: 2 x 2 changeover contacts or wide auxiliary voltage range
  • 2 possible compact designs:
    MK 9837N/5_0: Width 22,5 mm
    MH 9837/5_0: Width 45 mm