🔍 Key Concepts

• Review how a start/run (two-step) reduced-voltage starter works, especially the sequence from initial energizing to full-speed run. • Identify the symbols for the Start Contactor Rack Limit Switch (SRLS) and Run Contactor Rack Limit Switch (RRLS) in the diagram and note whether they are shown as normally open or normally closed in the control circuit. • Trace the control logic around the 1CR and 2CR relays during the transition from start to run and see which limit switches must be made for each mode to be maintained.

💭 Think About

• During the initial start sequence, which contactor has to be fully racked in and proven before the control circuit will allow current to flow to the motor? Which limit switch proves that condition? • Once the motor transitions to the run condition, which contactor must remain proven in to keep the motor energized, and what does that imply about the state of its associated rack limit switch? • If either rack-mounted contactor were to lose proper contact with the line/load stabs during operation, would you want its associated limit switch to be open or closed to safely de-energize the circuit?

✅ Before You Answer

• Verify which device each label refers to: SRLS = Start Contactor Rack Limit Switch and RRLS = Run Contactor Rack Limit Switch. • Check in the schematic whether the SRLS and RRLS contacts are drawn as normally open or normally closed in the control circuit, and note when each is picked up. • Confirm that in both the start and the run portions of the sequence, the motor should only be energized when the appropriate rack-mounted contactor is fully racked in and its limit switch is in the correct (made) position.