Power failure detector with switching contact

The power failure detector is a sensor for monitoring mains voltage. When one or more phases fail, the built-in relay switches.

This power failure detector has a universal alarm output with a voltage-free switch contact. Either an open or a closed contact is available in the presence or absence of mains voltage at the input.
Reset occurs automatically on return of mains voltage.

Monitoring of technical installations

The power failure detector is housed in a 35 mm DIN rail housing and is intended for fixed installations, such as in a control cabinet. Click for alternative: GSM power failure detector.
The alarm signal, in the form of a de-energised NO-NC contact, can be connected to a security system, control panel or other circuits for monitoring mains voltage.

Switching on auxiliary voltage

Special application: automatically control a relay to switch on another voltage as soon as the mains voltage is lost.
The red LED on the power failure detector lights up when mains voltage is present. For power current, this means that all 3 phases are present.

Monitoring 1 or 3 phases

The power failure detector has 4 connections for monitoring 3-phase AC voltage (380/400 volts) with neutral connection. It can also be used for single-phase mains voltage (220/230 volts).
The output terminal has 3 connections, for NO-COM-NC. Both input and output are designed as plug-in terminals. See figure for connection.

Power failure detector - technical info

•    Type: phase detector APS-100
•    Model: DIN relay
•    Input: 1/ 3 phases + neutral
•    Voltage: 220/380 V ±10%
•    Output: contact NO/NC
•    Switching current: 3 A (230 Vac)
•    Switching current: 3 A (30 Vdc)
•    Input voltage: 220/380 V
•    Monitored: 1 or 3 phases
•    Earth: not applicable
•    Omg. temp: -30...+90 C
•    Humidity: < 90% RH
•    Alarm tone: no
•    Indication: 1x LED
•    Reset button: no
•    Dimensions: 105x36x62 mm
•    Manual: EN

What is power failure?

Power failure is the popular approximation for loss of mains power. It can mean that mains power is no longer entering the building, or that a fault has occurred in the electrical system.