KFH-2-Element90

Supported Applications

The Omega KFH Series consists of pre-wired strain gages designed for strain measurement. These sensors feature a rugged polyimide carrier and full encapsulation to provide environmental protection at the measuring point, eliminating the need for soldering during installation.

Operating Conditions & Performance

The series operates within an ambient temperature range of -10 to 155 °C (-14 to 320 °F) for both static and dynamic measurements. The measuring grid is constructed from Constantan with a thickness of μm (microinch) 3.8 or 5 (150 or 197), depending on the strain gage type, mounted on a polyimide carrier.

Performance specifications include:

• Gage Factor Tolerance: ±1% for grid lengths of 0.6 mm and 1.5 mm; ±1.5% for other grid lengths
• Mechanical Hysteresis: 1 μm/m (microstrain) at the 1st load cycle with adhesive SG496, reducing to 0.5 μm/m (microstrain) at the 3rd load cycle
• Fatigue Life: Greater than 1 x 10⁷ cycles tested at alternating strain Lw = ±1000 μm/m with zero point variation ≤ 300; 5 x 10⁶ cycles with zero point variation ≤ 30
• Maximum Elongation: Absolute strain value of 20,000 ± 2% for the positive direction and 25,000 ± 2.5% for the negative direction (measured on linear 3 mm 120Ω gage at reference temperature)

Configuration Options

The KFH series is available in multiple configurations to accommodate specific measurement geometries and electrical requirements.

Gage Patterns

• Precision Linear Pattern (C1): Grid lengths range from 0.3 mm to 20 mm
• Precision Planar X-Y Pattern (D16): Grid lengths available in 0.6, 1.5, 3, and 6 mm
• Planar 0°/45°/90° Rosette Pattern (D17): Grid lengths available in 0.6, 1.5, 3, and 6 mm

Nominal Resistance & Electrical Connections

Models are offered with nominal resistances of 120 Ω or 350 Ω. The gages feature pre-wired connections consisting of PTFE wire (Ø - 0.051 mm², approximately 50 mm long) connected to AWG 28 ribbon cables (PVC insulated) through solder sleeves in either 2- or 3-wire configurations.

Lead Lengths & Termination

Variants include options for two 1 m leads or three 3 m leads. The series is temperature compensated for steel (ST).

Key Product Differences

The primary distinctions within the KFH Series are defined by the gage pattern, grid length, and nominal resistance.

• Linear vs. Planar: Linear patterns provide single-axis measurement with a wide range of grid lengths (0.3 mm to 20 mm). Planar X-Y and Rosette patterns are designed for multi-directional strain analysis in smaller footprints, typically ranging from 0.6 mm to 6 mm.
• Resistance Options: While linear gages offer both 120 Ω and 350 Ω options across various sizes, the planar X-Y (D16) and Rosette (D17) patterns listed in this series are available in 120 Ω or 350 Ω depending on the specific model number.
• Lead Configuration: Models differ by lead count and length; some configurations provide two leads of 1 m, while others offer three leads of 3 m to facilitate different bridge circuit setups.