The motor starts when the start button in...

The motor starts when the start button in...

Question 1 of 2707066636eed28f7522a1c51d7f9

The motor starts when the start button in the illustration is pushed, but stops when the button is released. What is most likely the trouble? Illustration EL-0007

Question 1 of 27070

Q

The motor starts when the start button in the illustration is pushed, but stops when the button is released. What is most likely the trouble? Illustration EL-0007

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🔍 Key Concepts

• Review how a three-wire motor control circuit works with Start/Stop pushbuttons and an auxiliary seal‑in (holding) contact labeled "M". • Trace the path of current to the M contactor coil when the Start button is pressed, and then when the Start button is released. • Consider what components must be working correctly for the motor to start at all, and which one keeps the circuit energized after the Start button is released.

💭 Think About

• When you press Start, which path energizes the M coil in the control circuit shown? Follow it from L1 through Stop, Start, M, and OL. • After you release the Start button, what part of the circuit is supposed to maintain the current path to the M coil so the motor keeps running? • Looking at each answer choice, ask: would this fault allow the motor and contactor to energize while the Start button is held, yet drop out immediately when it’s released?

✅ Before You Answer

• Verify which contact in the drawing is the holding (seal‑in) contact wired in parallel with the Start pushbutton. • Confirm that an open M coil would prevent the contactor from pulling in at all, not just after releasing Start. • Check that an open in the Stop button (normally closed) would interrupt current even while Start is pressed, so the motor would not start under normal wiring.