Open Drip Proof (ODP) motor design permits air exchange around windings within which angle range downward from the vertical?

• A. 0 to 30 degrees downward
• B. 0 to 10 degrees downward
• C. 0 to 15 degrees downward from the vertical
• D. Only at the top

Answer: (C)

Open Drip Proof (ODP) motors are designed to ventilate and cool the windings while keeping liquids from entering the housing. The vents around the windings are positioned to allow air to move for cooling when the motor is near vertical, but only within a small downward tilt. This keeps cooling air flowing without letting dripping liquids reach the windings. The specified range is from vertical down to 15 degrees downward. Tilting more than 15 degrees increases the risk that liquids could enter through the vents, so air exchange isn’t reliably maintained beyond that angle. So the best range is 0 to 15 degrees downward from the vertical.