Industrial Motor Control
7th Edition
ISBN: 9781133691808
Author: Stephen Herman
Publisher: Cengage Learning
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Chapter 44, Problem 13RQ
Refer to the schematic diagram in Figure 44–8. Assume that the motor is not running. When the 3rd 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 4th 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. S2 contactor coil is open.
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Chapter 44 Solutions
Industrial Motor Control
Ch. 44 - Prob. 1RQCh. 44 - Prob. 2RQCh. 44 - A wound rotor induction motor has a stator that...Ch. 44 - Name three factors that determine the amount of...Ch. 44 - Prob. 5RQCh. 44 - Explain why controlling the rotor current controls...Ch. 44 - Prob. 7RQCh. 44 - Prob. 8RQCh. 44 - What is rotor slip?
Ch. 44 - Prob. 10RQ
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- 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_forwardThe device that prevents the engine from turning the armature of the starter motor is the. overrunning clutch pinion gear flywheel pole shoearrow_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_forward
- Refer to the circuit shown in Figure 241. Assume that timer TR is set for a delay of 10 seconds. When the START button is pressed, the motor starts in low speed. After a delay of 30 seconds the motor is still in its lowest speed and has not accelerated to normal speed. Which of the following could not cause this condition? a. The START button is shorted. b. Timer coil TR is open. c. Contactor coil R is open. d. Timed contact TR did not close after a delay of 10 seconds.arrow_forwardThe supply frequency is 50 Hz. What will be the rotor voltage frequency if the motor speed is equal to 90% of synchronous speed. O 45 Hz. O 10 Hz. 05 Hz. O None.arrow_forwardThe reversing motor,which is controlled by two power relays,can be rotated in both directions as shown in the figure beiow.When the motor is mechanically combined with a lead screw,the rotary motion is converted to a linear one,such as the one moving lef tor right on the worktable in the layout.The desired direction of rotation is selected via the two STAFIT buttons,respectively.The limit switches LS1 and LS2,located at the two extreme motion limits,ensure 1-rqtf we forget to stop the movement of the worktable,then it will stop automatically, and the mechanism of the layout will not be destroyed.Draw the circuit of automation.arrow_forward
- Refer to the circuit shown in Figure 15-6. The STOP button is shown to be an emergency STOP button. What does the symbol used for the STOP button actually represent?arrow_forwardRefer to the circuit shown in Figure 16-11. Assume that the platform is located on the bottom floor. When the UP push button is pressed the pump motor does not start. Which of the following could not cause this problem? The contacts of limit switch LS1 are open. The contacts of limit switch LS2 are open. Motor starter coil M is open. The overload contact 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_forward
- Refer 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_forwardIn relation to the circuit presented below, mark the alternative(s) that you consider correct. 1 To enable actuator A2 to advance, it is necessary to switch valve V2 to the leftmost position and ensure that valve V1 is in its initial (intermediate) position. 2 Switching valve V2 to the leftmost position allows actuator A2 to advance, but for this to happen, valve V1 must also be switched to the leftmost position. 3 When activating valve V1, using the locking lever installed on the left side of it, the two actuators (A1 and A2) are allowed to advance. 4 Hydraulic pump B1 is a simple variable displacement type. 5 Valves V1 and V2 have a TANDEM center.arrow_forwardDesign the circuit (pneumatic/hydraulic/electro-pneumatic/electro-hydraulic) for the following problems:1.A double acting cylinder of pneumatic system will extend when two pushbuttons are pressed. The retraction is doneautomatically when either one of the pushbuttons is released.2A pushbutton is required to extend a cylinder of a pneumatic stamping machine. Once the cylinder at the full extensionposition, it will wait for 5 seconds before it is automatically retracted.3.The cylinder extends when two pushbuttons are pressed. The cylinder retracts when the set pressure of 5 bar is achieved.4.Given a hydraulic system with double acting cylinder. The cylinder extends when the lever is triggered. The retraction of thecylinder is achieved by another lever.arrow_forward
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