GE CR224 Series – Thermal Overload Relay

Technical Specifications

• Manufacturer: General Electric (GE)
• Model: CR224 (suffixes e.g., C610A, D310A denote current range/features)
• Type: 3‑pole thermal overload relay
• Voltage Rating: 600 VAC maximum
• Current Ranges:
  • CR224C610A: 21–27 A adjustable
  • CR224D310A: 28–45 A adjustable
  • Other variants: up to 110 A
• Contact Configuration: 1 NC (normally closed) auxiliary contact
• Mounting: Panel‑mount, direct coupling to GE contactors
• Ambient Compensation: Yes (compensates for surrounding temperature changes)
• Weight: ~1.15 lbs (0.52 kg)
• Dimensions (L×W×H): 5.25 × 4.25 × 3.75 in (133 × 108 × 95 mm)
• Operating Temperature: −20°C to +60°C
• Certifications: UL, CSA, CE (industrial control standards)

Key Features

1. Three‑Phase Overload Protection
   • Directly monitors current in all three phases of a motor.
   • Trips on sustained overload, locked rotor, or single‑phase operation.
2. Adjustable Current Setting
   • User‑adjustable trip current matches motor full‑load ampere (FLA) rating.
   • Ensures precise protection for a wide range of motor sizes.
3. Ambient Temperature Compensation
   • Internal bimetallic elements adjust for ambient temperature, preventing nuisance tripping in hot environments and ensuring protection in cold conditions.
4. Compact & Rugged Design
   • Heavy‑duty construction for long life in industrial environments.
   • Compact footprint fits standard control panels; directly mates with GE contactors for easy installation.
5. Isolated Auxiliary Contact
   • 1 NC contact for remote alarm, interlock, or control circuit shutdown.
   • Rated for pilot duty (600 VAC max).
6. Manual Reset Option
   • Standard manual reset after trip; some variants offer electrical reset.
   • Clear trip indicator for quick fault identification.

Application Scenarios

• Industrial Motor Control
  • Protects three‑phase AC motors in conveyors, pumps, fans, compressors, and machine tools.
  • Used in manufacturing, food & beverage, textile, and metalworking plants.
• HVAC & Building Services
  • Safeguards large HVAC fans, chillers, and water pumps in commercial buildings.
• Oil & Gas / Process Industries
  • Protects motors driving pumps, compressors, and mixers in refineries, chemical plants, and pipelines.
• Power Generation
  • Used in auxiliary motor control systems in power plants (thermal, hydro).
• Marine & Offshore
  • Suitable for motor control on ships, offshore platforms, and port facilities (within temperature and voltage ratings).