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Relay Finder will let you know, when one phase is missing ...

Finder monitoring relays are able to effectively signalize a fault status in a mains line and to prevent damages or undue wear-out.

Too high or too low voltage, phase loss or a wrong phase rotation are conditions commonly occurring in an industrial environment. Even though a phase rotation is usually stable, but only one improperly connected lengthening cable is sufficient .... These fault conditions harm to typical 3-phase devices like for example motors and as for a voltage out of tolerance - this usually doesn´t make well to any device. Devices like compressors and gas discharge lamps even don´t like too often switch on/ off (cycling) in case of fault conditions in the mains power line. There is a solution for all these cases - in a form of a simpler of a more sophisticated monitoring relay.
In our offer can be found high-quality components from company Finder - a producer with long-term experience in production of relays. To components intended for monitoring of mains line belong for example series F70 and F71, from which we keep in stock these types: - 3-phase electronic monitoring relay. Monitors low voltage (adjustable), high voltage (adjustable), window mode (low + high voltage), adjustable time delay of switching (trip), selectable fault memory, phase loss, phase rotation. Comprehensive indication of all statuses by means of three LEDs - compact 3-phase electronic monitoring relay. Monitors phase rotation and phase loss. - 3-phase monitoring relay. Monitors low voltage (adjustable), high voltage (overvoltage), adjustable time delay of switching (trip), selectable fault memory.

All above mentioned types have on their output a small relay (6 or 10A), which can serve for controlling of a main contactor or directly for switching of other devices in case of faulty status. Adjustable time delay at types 70.31 and 71.31 functions in a way that after detection of a fault a relay “waits” for a selected time and if a fault still persists, the relay will switch on an output contact. In other words - monitoring relay ignores faults shorter than a selected time (0.5-60s at type 70.31 and 0.1-12s at type 71.31). This function is very useful to prevent an undue frequent switch on/off of devices, which are able to withstand a short-time fault status without a damage.

Memory function is also a useful function, which - if active, will prevent a repeated start of a device. This is very important for example at devices, which mustn´t be switched on without an operating personnel.

Detailed description can be found in datasheets at particular types.
In case of interest in any monitoring relay Finder, please contact us at

Advantages/ Features:

  • mains line monitoring relay
  • monitors voltage, phase rotation and phase loss
  • important component for protection of devices
  • other types also available (monitoring of phase asymmetry, …)
  • adjustable delay time (ignoring of short-time faults)
  • selectable fault memory

Additional products
image type / kind / description Ord.number manufacturer in stock External stock price/pc excl. VAT FINDER

Monitoring relay 1c 6A 400VAC

More info: F70EN.pdf

Monitoring Relays



in stock 1 pcs

1 pcs+ 61,4000 €

2 pcs+ 56,3000 €

10 pcs+ 48,7000 €

25 pcs+ 46,9000 € FINDER

Monitoring relay 1c 6A 400VAC IP20

More info: F70EN.pdf

Monitoring Relays



in stock 3 pcs

1 pcs+ 42,5000 €

2 pcs+ 38,9000 €

5 pcs+ 37,2000 €

20 pcs+ 32,6000 € FINDER

Monitoring relay 1c 10A 400VAC

More info: F71EN.pdf

Monitoring Relays



in stock 2 pcs

1 pcs+ 76,8000 €

2 pcs+ 74,3000 €

5 pcs+ 70,9000 €

20 pcs+ 62,6000 €

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