CN1566, CN2086, CN2586, CN3086, CN3586, CN4086 and CN5086 Electric Motors Caterpillar

Pt-100 Resistance Temperature Detectors

Pt-100 resistance temperature detectors are an essential part in the condition monitoring and protection system of the motor. Pt-100 resistance temperature detectors are used to measure temperatures in the windings, bearings, and in the cooling air. The Pt-100 detectors use a fine platinum filament for the temperature measurement, which can be damaged by incorrect handling or excessive vibration.

The following symptoms might suggest a problem in a Pt-100 detector:

• Infinite or zero resistance over the detector.

• Disappearance of measurement signal during, or after startup.

• A significant resistance value difference in a single detector.

If a Pt-100 failure is suspected, confirm the findings from the connection box by measuring the resistance at the detector with the cables disconnected. Register the findings. For resistance values at different temperatures, see Table 1.

There are two possible ways to remedy stator Pt-100 damage. If there are operational spare detectors remaining in the stator core, these detectors can be taken into use. If all the working factory assembled detectors are in use, a new detector can be retrofitted in the winding end.