Thermometrics BTC series bearing thermocouples provide direct contact temperature measurement at rotating equipment bearing housings. Bayonet-lock or spring-loaded designs ensure positive, repeatable contact between the copper measuring tip and the bearing housing bore regardless of vibration and thermal cycling.
A bearing thermocouple with a bayonet-lock fitting and copper sensing tip for direct thermal contact with a bearing housing bore. The bayonet locks the sensor at a fixed depth with a quarter-turn action, ensuring consistent insertion depth and contact force on every installation. The copper tip maximises thermal conductivity between the housing and the thermocouple junction.
The BTC-BAY adds a flexible spring between the sensor body and the bayonet lock, maintaining consistent contact force even as the bearing housing expands and contracts thermally. The spring travel also accommodates minor variations in housing bore depth between bearing stands. Copper tip, Type K or J, faster thermal response than rigid BTC-44.
The bearing sensor RTD version — Pt100 Class A element in a spring-loaded bayonet body with copper tip. Provides higher accuracy than the TC version, suitable for critical bearing applications where temperature rise above baseline is the key diagnostic parameter. 3-wire, compatible with standard bearing temperature monitoring systems and vibration protection panels.
| Parameter | BTC-44 | BTC-BAY | BTC-RTD |
|---|---|---|---|
| Sensor Type | Type K or J TC | Type K or J TC | Pt100 Class A RTD |
| Tip Material | Copper | Copper | Copper |
| Lock Type | Bayonet — fixed depth | Bayonet + spring — variable depth | Bayonet + spring — variable depth |
| Spring Travel | None | 5mm typical | 5mm typical |
| Body Material | Brass or SS | Brass or SS | SS |
| Max Temp | 150°C (PTFE lead) | 150°C (PTFE lead) | 150°C |
| Lead Wire | PTFE 24 AWG, 36" | PTFE 24 AWG, 36" | PTFE 3×24 AWG, 36" |
| Tolerance | ASTM E230 Std | ASTM E230 Std | IEC 60751 Class A |
API 670 (Machinery Protection Systems) specifies requirements for bearing and winding temperature monitoring on critical rotating equipment. RTD sensors (typically Pt100 or Pt200, Class A) are preferred over thermocouples for bearing temperature measurement in API 670 systems because of their higher accuracy and better long-term stability. The BTC-RTD is compatible with API 670-compliant machinery protection panels and vibration monitoring systems.
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