🔍 Key Concepts

• Auxiliary contacts on contactors (difference between normally closed (NC) and normally open (NO) in control circuits • How electrical interlocks prevent two opposite-direction contactors (hoist vs lower) from energizing at the same time • How control power is routed or "extended" to speed control circuits through auxiliary contacts when a direction is selected

💭 Think About

• On the schematic, follow the path feeding the hoist coil and then the lower coil: which auxiliary contacts are in series with the opposite coil, and are those contacts NC or NO? • Then, follow the path that leads from the master switch toward the speed-control or timing circuits: which auxiliary contacts must change state (close) when a contactor pulls in to send power onward? • Ask yourself: do both NC and NO contacts serve the same function, or is one type mainly for interlocking and the other for feeding the speed circuits?

✅ Before You Answer

• Verify which auxiliary contacts open whenever the hoist contactor is energized and see how that affects the lower contactor coil circuit (and vice versa) — this points to the interlock function. • Confirm which auxiliary contacts must close when a direction (hoist or lower) is selected in order to energize the speed-control (1A, 2A, 3A, 4A, TC, etc.) circuits. • Check whether the diagram shows both NC and NO aux contacts used for interlock only, or if some clearly feed onward to additional control circuits; eliminate any answer choice that doesn’t match what you trace on the diagram.