🔍 Key Concepts

• Time-delay relay vs. instantaneous relay symbols in motor control diagrams • How a reduced‑voltage (autotransformer) starter switches from start to run • Which device’s contacts actually drop out one contactor and pick up another after a delay

💭 Think About

• On the right‑hand (control) side, trace what happens when S2 (start) is pressed: which coil energizes first, and which device controls what happens a few seconds later? • Look for the relay or contactor that is explicitly marked with a delay and whose contacts are in series with the coils that change the circuit from transformer‑start to full‑voltage run. • Compare the roles of KM1, KM2, and KM3: which ones simply connect power, and which labeled device is there only to provide a timed changeover?

✅ Before You Answer

• Identify the symbol(s) labeled (Delay) in the diagram and note their designation letters. • Verify which device’s contacts are used to switch from the ‘starting’ contactors to the ‘running’ contactor. • Confirm that KM1, KM2, and KM3 are power contactors without inherent timing, and that the timing function is provided by a separate time‑delay relay.