Overview
The Furnas K34 is a Class 14 bimetallic thermal overload heater element manufactured by Siemens/Furnas Electric Co. This heater is designed for use with thermal overload relays and magnetic motor starters to provide reliable overcurrent protection in three-phase motor control applications. The K34 model covers a full load motor amperage range and integrates seamlessly into standard NEMA 00/0/1/1P enclosures.
Key Features
- Current Rating: Rated for 4.01–4.35 amps for some applications and 4.80–5.21 A for others depending on control size and enclosure class
- Bimetallic Design: Class 14 bimetallic material for consistent, ambient-compensated thermal response
- Wide Compatibility: Fits standard thermal overload relay sockets in NEMA-rated motor starters
- Proven Construction: Tubular heater element design, weighs 0.10 lbs
- Ambient Temperature Compensation: Maintains accurate trip performance across varying ambient conditions
Technical Specifications
- Full Load Amperage Range (FLA): 4.01–5.21 A (varies by control size and trip class)
- Trip Class: Class 10 and Class 14 (depending on application)
- Material: Class 14 bimetallic element
- Enclosure Compatibility: NEMA 00/0/1/1P
- Weight: 0.10 lbs
- Type: Thermal overload heater element
- Manufacturer: Siemens/Furnas Electric Co.
- Ambient Compensation: Yes—automatically adjusts for ambient temperature variations
Typical Applications
The K34 heater is used across industrial and commercial motor control systems:
- Fractional Horsepower Motors: Protection for small AC induction motors in machine tool applications
- HVAC Systems: Pump and fan motor protection in heating and cooling equipment
- Conveyor Systems: Reliable overload protection for light-duty conveyor drive motors
- Automated Equipment: Motor protection in assembly lines and packaging machinery
- Machine Tools: Spindle and feed motor protection in milling machines and lathes
Compatibility & Replacements
Compatible With
- Furnas thermal overload relays and magnetic motor starters (all sizes fitted for K series heaters)
- Siemens motor control products that accept K series thermal heater elements
- Standard NEMA motor starter enclosures (00, 0, 1, 1P)
- Three-phase and single-phase motor circuits rated for the K34 amperage range
Replaces / Drop-In Replacement For
- OEM Furnas K34 heater elements in thermal overload relays
- Siemens K34 thermal heater replacements (cross-compatible product lines)
- Direct substitute for worn or damaged K34 heaters in existing motor starter assemblies
Works With
- Furnas/Siemens thermal overload relay assemblies
- Magnetic motor starters with thermal overload protection
- AC induction motor branch circuits (single-phase and three-phase)
- Motor control enclosures rated NEMA 1, 3R, 4, 12, and similar indoor/outdoor protection classes
