🔍 Key Concepts

• Open drip-proof (ODP) motors have ventilation openings that allow air to circulate through the windings, but are shaped/located so that water dripping from above (within about 15° from vertical) cannot fall directly on live parts. • Compare an ODP enclosure with a totally enclosed fan-cooled (TEFC) motor, which has a solid frame with external fins and usually a fan shroud, and with a completely open/skeleton type where the internal parts are visibly exposed. • Look closely at the end bells and side vents on each illustrated motor to see how much of the interior you can see and whether there is any drip shielding.

💭 Think About

• Which motor shows clear ventilation slots or openings into the interior, but those openings are partly shielded or directed downward so that direct vertical drips would be deflected? • Which motors look more like fully enclosed machines with solid frames and external fins or covers, and which one looks so open that water could easily fall straight onto the windings? • If you imagine rain or condensation dripping from directly overhead, on which motor would the construction reasonably protect against vertical drips while still allowing internal airflow?

✅ Before You Answer

• Identify which choice has visible vents/slots with some form of cover or hood, rather than a smooth, fully closed frame. • Eliminate any motor where the rotor and windings are plainly exposed with no drip protection at all. • Eliminate any motor with a completely sealed-looking, finned housing and external fan shroud, as those are characteristic of TEFC, not open drip-proof.