FGT-Series

Supported Applications

The Omega FGT Series Bi-Metal Inline Thermostat is designed for use in electric/hybrid vehicles and special-purpose vehicles. The series functions as a bi-metal thermostat for heating elements, featuring reliable bi-metal technology with normally closed contacts intended for heating applications.

Operating Conditions & Performance

The FGT Series operates across two distinct voltage ranges: 100 Vac to 230 Vac (High Voltage) and 12 Vdc to 24 Vdc (Low Voltage). Switching temperatures are pre-set at specific points depending on the model. High Voltage models offer switching temperatures of 5°C/41°F or 20°C/68°F, while Low Voltage models provide identical temperature setpoints.

Performance characteristics differ by voltage class:

• High Voltage (FGT310, FGT311): Features a snap bi-metal action with 10°C/18°F hysteresis. Current ratings are up to 15 A at 125 Vac and 10 A at 230 Vac.
• Low Voltage (FGT308, FGT309): Features a creep bi-metal action with an endurance of 100,000 cycles. Current ratings are up to 5 A at 24 Vdc and 3 A at 12 Vac/dc.
• Tolerance: The specifications table lists a tolerance of +/- 3°C for Low Voltage models; no specific tolerance value is provided in the source data for High Voltage models.

The series carries CE and UKCA approvals. Enclosure protection is rated IP20, with Protection Class I specified for Low Voltage configurations.

Configuration Options

The FGT Series offers four distinct part numbers configured by voltage class and switching temperature:

• High Voltage Models (FGT310, FGT311):
• Switching Temperature: 5°C/41°F or 20°C/68°F.
• Voltage Range: 100 Vac to 230 Vac.
• Action Type: Snap bi-metal action.
• Low Voltage Models (FGT308, FGT309):
• Switching Temperature: 5°C/41°F or 20°C/68°F.
• Voltage Range: 12 Vdc to 24 Vdc.
• Action Type: Creep bi-metal action.

All models utilize a self-assembly component design. Electrical connections are made via crimp terminals compatible with wire sizes from 0.34 mm² to 1.5 mm² (22 AWG to 16 AWG). The wiring includes red silicone wire, specified as 20 AWG (0.5 mm²) in the High Voltage configuration.

Key Product Differences

The primary distinction within the FGT Series is between High Voltage and Low Voltage configurations, which differ in physical dimensions, electrical ratings, and bi-metal action type:

• Dimensions (W x L x H): High Voltage models measure 17 mm x 45 mm x 14 mm. Low Voltage models are smaller at 8 mm x 45 mm x 8 mm.
• Action Mechanism: High Voltage units utilize a snap action, whereas Low Voltage units employ a creep action.
• Endurance: The source specifies an endurance of 10,000 cycles for nominal approvals on High Voltage models and 100,000 cycles for Low Voltage models.