The component designated by the National Stock Number (NSN) 6685-00-150-6540 represents a critical piece of instrumentation in temperature monitoring systems: an ELECTRICAL RESISTANCE TEMPERATURE TRANSMITTER. This device functions by utilizing a temperature sensing element whose inherent electrical resistance changes proportionally with variations in temperature.
Core Functionality and Application
The primary role of this transmitter is to convert thermal input into an electrical signal, transmitting temperature-related information to a corresponding INDICATOR, TEMPERATURE, ELECTRICAL RESISTANCE. It is important to note its relationship with other instruments; it may serve as an integral component within a THERMOMETER, INDICATING, RESISTANCE or a THERMOMETER, RECORDING, RESISTANCE. This specific classification distinguishes it from other temperature sensing devices like the THERMOCOUPLE.
Technical Specifications
A close examination of the technical data associated with NSN 6685-00-150-6540 reveals several key design characteristics:
- Unit Type: PROTECTIVE TUBE
- Style Designator: TRANSMITTER, 24V DC. This indicates the operational power requirement for the transmission capability.
- Operating Temperature Range: The device is rated to accurately monitor temperatures from -17.8 to +237.8 Degrees Celsius.
- Mechanical Interface Details:
- Distance Across Wrenching Surface Flats: 0.500 Inches Nominal
- Outside Diameter: 0.250 Inches Nominal
- Overall Length: 2.156 Inches Nominal
- Thread Length: 0.380 Inches Nominal
- Mounting and Connection: It utilizes 1 THREAD for mounting, specified with the mounting facility screw thread series designator UNF. It accommodates 1 STUD contact type.
Manufacturer and Cross-Reference Data
This specific part number configuration sees production or supply from multiple established manufacturers, as indicated by the cross-reference data:
- CESSNA AIRCRAFT COMPANY (DBA TEXTRON AVIATION), associated with Cage Code 71379, lists the alternate part number S1372-1.
- STEWART-WARNER CORPORATION, associated with Cage Code 57733, lists the alternate part number 333B.
The inclusion of manufacturers like Cessna strongly suggests that this particular model of temperature transmitter is utilized within demanding aerospace or defense applications, such as maintaining critical temperature metrics within complex machinery.
Real-World Context: End Use
The documentation specifies the End Item Identification for this part includes RADAR SYSTEMS, PHASE ARRAY FPPS-85″. This application underscores the necessity for high reliability and precise temperature regulation, as inaccuracies in monitoring resistance temperature transmitters within radar systems can directly impact performance and system integrity.
The various part numbers associated with this NSN—including 6685001506540, S1372-1, and 333B—ensure robust supply chain support for systems requiring this specific 24V DC electrical resistance temperature sensing capability.