Finder 70.92.8.230.0002 – 70 Series Line Monitoring relays

Why Choose the Finder 70.92.8.230.0002 Thermistor Monitoring Relay?

The Finder 70.92.8.230.0002 is an industrial PTC thermistor temperature monitoring relay designed to protect electric motors and machinery against excessive operating temperatures. Part of the Finder Series 70, this relay monitors PTC thermistor sensors and provides protective switching when an excessive temperature or sensor circuit fault is detected.

Operating from a 230 V AC, 50/60 Hz supply, the Finder 70.92.8.230.0002 features two changeover output contacts (2 CO / DPDT) rated at 8 A at 250 V AC. Its monitoring functions include PTC temperature detection, sensor short-circuit detection and sensor wire-break detection, making it suitable for industrial applications requiring temperature-dependent protection and fault signalling.

With six selectable operating functions, LED status indication, external reset terminals and a compact 22.5 mm DIN rail housing, this thermistor monitoring relay provides flexible integration into motor control panels and industrial automation systems. Its positive safety logic supports protective control arrangements in which a detected fault causes the relevant normally open output contact to open.

Key Advantages

• PTC thermistor temperature monitoring for electric motor and machinery protection.
• 230 V AC supply for compatible industrial control installations.
• Two changeover contacts (2 CO / DPDT) for protective switching and signalling.
• 8 A contact rating at 250 V AC for appropriately rated electrical circuits.
• PTC sensor short-circuit detection to identify faults in the sensing circuit.
• PTC sensor wire-break detection to monitor sensor circuit continuity.
• Six selectable operating functions with different fault-memory and reset behaviours.
• Selectable 0.5 s or 3 s reset delay for control flexibility.
• Positive safety logic for fault-responsive output operation.
• LED status indicators for convenient local diagnostics.
• External reset terminals for integration into industrial control systems.
• 35 mm DIN rail mounting for straightforward panel installation.
• 22.5 mm housing width for space-efficient control cabinet layouts.

Key Features

• Finder Series 70 temperature monitoring relay.
• Type 70.92 PTC thermistor monitoring.
• Nominal supply voltage: 230 V AC.
• Supply frequency: 50/60 Hz.
• Operating supply range: 184–253 V AC.
• Output configuration: 2 CO (DPDT).
• Rated contact current: 8 A.
• Rated contact voltage: 250 V AC.
• AC-1 switching capacity: 2,000 VA.
• AC-15 switching capacity at 230 V AC: 400 VA.
• PTC thermistor short-circuit and wire-break detection.
• Six selectable monitoring functions.
• Fault-memory and non-memory operating modes.
• Selectable reset delay: 0.5 s or 3 s.
• External reset terminals.
• LED operating and fault indication.
• AgNi contact material.
• IP20 degree of protection.
• Screw terminal connections.
• 35 mm DIN rail mounting in accordance with EN 60715.

Reliable 230 V AC PTC Thermistor Protection for Industrial Motors

The Finder 70.92.8.230.0002 provides temperature-dependent protection by monitoring the resistance of connected PTC thermistor sensors. As the monitored temperature rises towards the sensor's characteristic response temperature, the PTC resistance increases. The relay detects the resulting condition and changes the state of its output contacts, allowing the control system to initiate a protective response.

In a typical motor protection installation, the relay's two changeover contacts can be incorporated into a contactor control circuit, fault alarm system or compatible automation controller. When an excessive temperature or sensor circuit fault is detected, the relay can provide a switching signal to stop the motor, indicate a fault or initiate another protective action according to the installation design.

The device also detects PTC short circuits and wire breaks, supporting monitoring of the temperature sensing circuit itself. Its six operating functions include fault-memory and non-memory modes, with selectable reset behaviour and delay settings. The Finder 70.92.8.230.0002 is a temperature monitoring relay, not a substitute for thermal overload protection, short-circuit protection or other protective devices required by the complete electrical installation.

Typical Applications

• Electric motor winding temperature monitoring.
• Industrial motor thermal protection circuits.
• Industrial pumps and pumping station control panels.
• Compressors and motor-driven machinery.
• Conveyor and material handling equipment.
• Hoists, cranes and lifting machinery.
• Industrial fans and ventilation systems.
• Manufacturing and woodworking machinery.
• PTC thermistor sensor fault detection.
• Industrial automation and PLC fault signalling.
• Machine protection and temperature monitoring panels.
• OEM electrical control equipment using 230 V AC supplies.