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

Advantages/ Features:

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

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

Date of publishing 2014-03-13
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On-line information from SOS electronic
Updated 2016-05-28 04:30:29
Order number, Kind of Product
Manufacturer (Brand)In stock
*External stock
Price excl.VAT

Monitoring relay 1c 6A 400VAC
Order number: 158408, S, RoHS
More info: F70EN.pdf
Monitoring Relays
1 pcs
61.4000 EUR

Monitoring relay 1c 6A 400VAC IP20
Order number: 144698, S, RoHS
More info: F70EN.pdf
Monitoring Relays
9 pcs
40.9000 EUR
2+/37.5000 EUR
5+/35.9000 EUR

Monitoring relay 1c 10A 400VAC
Order number: 67971, S, RoHS
More info: F71EN.pdf
Monitoring Relays
2 pcs
76.8000 EUR
2+/74.3000 EUR
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