DC Traction Motor EMD D29

The D29 traction motor features a compact structure and relatively light weight, making it suitable for narrow-gauge locomotives with limited space while still maintaining high traction performance. Its design is similar to that of the D31 motor, with some interchangeable components such as the armature, though differences exist in insulation, winding, and bearings. Renowned for its high reliability and maintainability, the D29 can be overhauled and extended in service life through processes such as rewinding the main field coils, replacing bearings, and renewing insulation materials. It was widely equipped on EMD export narrow-gauge locomotives such as the G18 and DDM45, becoming one of the classic models in international railway traction systems.

Operating Conditions
The motor should operate normally under the following conditions:
a. Altitude not exceeding 1200 m;
b. Ambient air temperature not lower than -25 °C, and not higher than 55 °C (when above 40 °C, for every 4 °C increase, the rated current shall be reduced by 1%);
c. In the most humid month, the monthly average maximum relative humidity shall not exceed 90% (with the same month’s average minimum temperature not higher than 25 °C).

Temperature Rise Limits
When the motor is tested at a voltage of 426 V, a current of 478 A, and under full field excitation, starting from actual cold state for a one-hour temperature rise test, and also during long-duration temperature rise tests at rated voltage, rated current, and full field excitation, the temperature rise limits for each component are as follows