🔍 Key Concepts

• Trace which master switch (MS) contacts close only in the fifth point for hoist and lower • Follow the control circuit to see which contactor coil (1A–5A) and which time delay relay (1T–3T) must energize to reach fifth speed • Compare what would happen if a contact is welded closed, fails to close, or a coil is open-circuited (cannot energize)

💭 Think About

• Looking at the MS contact chart on the left, which MS contact first becomes involved when moving from fourth to fifth point? How does that differ from the contacts used in the lower points? • In the ladder diagram on the right, which coil has to energize to change from fourth to fifth speed? What contact(s) in series with that coil would prevent it from picking up? • If the winch works normally in all other speeds and both directions, which component failures would affect only fifth speed instead of multiple speeds?

✅ Before You Answer

• Verify exactly which MS contact(s) close only at position 5 and are not used at positions 1–4 • Identify the path feeding the 5A coil and confirm which MS contact is in series with it for hoist and for lower • Check which options would cause problems in other speeds (not just fifth), and eliminate those that wouldn’t allow normal operation in 1st–4th speeds