Schneider TeSys LT3 Series PTC Thermistor Protection Relays

Schneider TeSys LT3 Series PTC Thermistor Protection Relays Suppliers, Exporters in India

Schneider TeSys LT3 Series PTC Thermistor Protection Relays are designed to protect electric motors and other equipment against overheating by continuously monitoring PTC thermistor sensors installed in the motor windings or protected equipment. Instead of measuring motor current, the LT3 Series responds directly to the temperature detected by the PTC probes, helping prevent insulation damage and extending motor service life.

The TeSys LT3 range is suitable for motors operating under demanding conditions where thermal overload relays alone may not provide sufficient protection. These relays are commonly used with motors that experience frequent starts, variable loads, or operate in high ambient temperatures. Depending on the model, the series offers automatic or manual reset options along with visual status indication for easier monitoring and maintenance.

The LT3 Series is simple to install and integrates easily into industrial control panels through cage connector terminals. Although Schneider Electric has replaced this product family with the Harmony RM35 Temperature Relay range, LT3 relays remain widely installed and are still required for maintenance, replacement, and retrofit applications.

Note: The TeSys LT3 Series has been replaced by the Schneider Harmony RM35 Temperature Relay series.

Models Covered

The TeSys LT3 Series includes the following models:

• LT3-SE – Automatic Reset
• LT3-SA – Automatic Reset with Voltage Fault Indicator
• LT3-SM – Manual Reset with Voltage Fault Indicator, Test and Reset Buttons

Specifications

• Product Name: Schneider TeSys LT3 Series PTC Thermistor Protection Relays
• Product Family: TeSys
• Relay Type: PTC Thermistor Protection Relay
• Application: Motor and Equipment Overtemperature Protection
• Temperature Sensing: PTC Thermistor Probes
• Reset Options: Automatic or Manual (model dependent)
• Status Indication: LED Voltage/Fault Indicator (selected models)
• Control Functions: Test and Reset Buttons (LT3-SM)
• Connection Type: Cage Connector Terminals
• Mounting: Panel or DIN Rail Mounting (configuration dependent)
• Monitoring: Motor Winding Temperature
• Replacement Series: Schneider Harmony RM35 Temperature Relays

Features

• Monitors motor temperature using PTC thermistor probes
• Protects motors against overheating
• Available with automatic or manual reset
• Voltage fault indication on selected models
• Built-in test and reset functions on LT3-SM
• Simple wiring using cage connector terminals
• Fast response to abnormal temperature rise
• Helps extend motor service life
• Suitable for demanding industrial environments
• Easy installation and maintenance
• Compatible with motors fitted with PTC sensors

Applications

• Three-phase motor protection
• Industrial automation systems
• Pumps and compressors
• Fans and blowers
• Conveyor systems
• HVAC equipment
• Water and wastewater treatment plants
• Mining and cement industries
• Textile machinery
• Packaging equipment
• Protection of bearings
• Protection of resistors
• Capacitor bank protection
• Motors with frequent starting cycles
• Equipment operating in harsh environments