As shown in figure "A" of the illustration, if in troubleshooting the control circuit using on-line techniques with a voltmeter with the start button depressed and the following readings are taken, what is the problem? "X1" to "X2" reads 115 VAC; "1" to "X2" reads 115 VAC; "2" to "X2" reads 0 VAC; and "3" to "X2" reads 0 VAC. Illustration EL-0123

Question

As shown in figure "A" of the illustration, if in troubleshooting the control circuit using on-line techniques with a voltmeter with the start button depressed and the following readings are taken, what is the problem? "X1" to "X2" reads 115 VAC; "1" to "X2" reads 115 VAC; "2" to "X2" reads 0 VAC; and "3" to "X2" reads 0 VAC.   Illustration EL-0123

Accepted Answer

Option C: the stop button is open-circuited. Voltage reading drops to 0 VAC at point 2 because the open stop button interrupts continuity upstream. Following IEEE 45 troubleshooting methods, power reaches the line side of the stop button, but the open contact blocks transmission further down the control loop.