EBK 3N3-EBK: INDUSTRIAL MOTOR CONTROL
7th Edition
ISBN: 9780176919962
Author: Herman
Publisher: VST
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Question
Chapter 43, Problem 13RQ
To determine
The reason that prevents the reversing contactor from energizing when the plugging switch contact is closed.
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Chapter 43 Solutions
EBK 3N3-EBK: INDUSTRIAL MOTOR CONTROL
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- Refer to the schematic diagram in Figure 318. Assume that the motor is not running. When the third speed push button is pressed, the motor starts in its lowest speed. After a delay of 3 seconds, the motor accelerates to second speed and 3 seconds later to third speed. After a period of about 1 minute, the fourth speed push button is pressed, but the motor does not accelerate to fourth speed. Which of the following could cause this problem? a. Control relay CR2 coil is open. b. S2 contactor coil is open. c. CR3 coil is shorted. d. S3 contactor coil is open.arrow_forwardRefer to the circuit shown in Figure 33–7. When the low speed push button is pressed, the motor begins to run in low speed. When the high speed push button is pressed, the motor stops running. Which of the following could cause this problem? The 1L contactor coil is open. H contactor coil is open. PR relay coil is open. The 2L contactor coil is open.arrow_forwardRefer to the circuit shown in Figure 97. Assume that when the forward push button is pressed the motor does not start, but when the reverse push button is pressed the motor will start in the reverse direction. When the stop button is pressed the motor stops running. Which of the following could NOT cause this problem? a. The forward push button is defective. b. The F starter coil is open. c. The overload auxiliary contact is open. d. The normally closed R contact is open.arrow_forward
- Refer to the circuit shown in Figure 25–5. Assume that timer TR1 is set for a delay of 10 seconds and timer TR2 is set for a delay of 5 seconds. When the START button is pressed, the motor starts. After 10 seconds the S1 contacts open and the motor continues to accelerate, but never reaches full speed. After a delay of about 30 seconds, the motor trips out on overload. Which of the following could cause this problem? TR1 coil is open. S2 coil is open. S1 coil is open. R coil is open.arrow_forwardRefer to the circuit shown in Figure 4221. Assume that the THIRD SPEED push button is pressed. The motor starts in second speed, skipping first speed. After 5 seconds, the motor accelerates to third speed. Which of the following could cause this problem? a. S1 contactor coil is open. b. CR1 contactor coil is open. c. TRl timer coil is open. d. S1 load contacts are shorted.arrow_forwardRefer to the circuit shown in Figure 5-29. In this circuit, the HR contactor is equipped with five contacts. Three are load contacts and two are auxiliary contacts. From looking at the schematic diagram, how is it possible to identify which contacts are the load contacts and which are the auxiliary contacts? Figure 5-29 The contactor contains both load and auxiliary contacts.arrow_forward
- Refer to the schematic in Figure 7-10. Assume that when the START button is pressed, the control transformer fuse blows. What is the most likely cause of this trouble? Figure 7-10 Numbers are placed beside all components.arrow_forwardRefer to the circuit shown in Figure 16-11. Assume that the platform is located on the lower floor. When the UP push button is pressed, the platform rises. When the platform reaches the upper floor, however, the pump does not turn off but continues to run until the overload relay opens the overload contacts. Which of the following could cause this problem? a. The solenoid valve opened when limit switch LS1 opened. b. The UP push button is shorted. c. Limit switch LS1 did not open its contacts. d. Limit switch LS2 contacts did not reclose when the platform began to rise.arrow_forwardRefer to the circuit shown in Figure 107. Assume that when the start button is pressed the motor does not start, but when the inch push button is pressed the motor runs at reduced speed. Which of the following could NOT cause this problem? a. The control transformer fuse is blown. b. M starter coil is defective. c. The start push button is defective. d. The stop push button is defective.arrow_forward
- Refer to the circuit shown in Figure 2614. When the START button is pressed, the control transformer fuse blows immediately. Which of the following could not cause this problem? a. Control relay coil CR is shorted. b. Starter coil 1M is shorted. c. Contactor coil S is shorted. d. Contactor coil 2M is shorted.arrow_forwardTo answer the following questions refer to the circuit in Figure 416. When the pressure switch closes, which starter will energize first, 1M or 2M? Explain your answer.arrow_forwardTo answer the following questions refer to the circuit shown in Figure 4110. Assume that the third speed push button is pressed and the motor starts in its first or lowest speed. After a delay of 3 seconds, the motor accelerates to its second speed, but never accelerates to its highest or third speed. Which of the following could cause this problem? a. CR coil is open. b. Coil 2TR is open. c. Coil 1TR is open. d. Coil 1S is open.arrow_forward
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