Electric Motor Control
10th Edition
ISBN: 9781133702818
Author: Herman
Publisher: CENGAGE L
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Chapter 60, Problem 7SQ
To determine
Choose the option that does not represent the cause for the problem that exists in the motor.
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c) Based on Figure 3 (c), a basic DOL starter induction motor at a power station is
experiencing run-time error and unable to start, based on your understanding,
interpret the sequence of troubleshooting shall be carried out to identify the root
cause of the abnormalities.
3P
1P
MCB
MCB
STOP
K1
START
MOTOR
Figure 3 (c)
Assume all of the timers are set for a 3 second delay. When the start button is pressed, nothing happens. None of the motors start. Which of the following could NOT cause this problem.
a
Overload contact OL1 is open
b
1CR relay coil is open
c
2CR relay coil is open
d
The stop button is open
20.a. A capacitive sensor is used to detect the presence of _______ objects.A. ferrousB. nonmovingC. nonconductiveD. magnetic20.b. A three-phase motor can be made to run backwards byA. connecting a resistor in series with the armature.B. reversing the control voltage connections.C. reversing three of its power leads.D. reversing two of its power leads.
Chapter 60 Solutions
Electric Motor Control
Ch. 60 - What are the three main electrical test...Ch. 60 - What is the advantage of a plunger-type voltage...Ch. 60 - A motor is tripping out on overload. The motor...Ch. 60 - A motor is tripping out on overload. The motor...Ch. 60 - Refer to the circuit shown in Figure 6016. The...Ch. 60 - Refer to the circuit shown in Figure 6016. Assume...Ch. 60 - Prob. 7SQCh. 60 - Prob. 8SQCh. 60 - Refer to the circuit shown in Figure 6016. If a...Ch. 60 - Prob. 10SQ
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- You’re powering up a new motor in a brushless motor control system. After moving the shaft of the motor lightly left to right, the motor reverses direction and runs away. What’s the problem? A. Power transistor failureB. Wrong motor typeC. Reversed tachometerD. Reversed hall-effect sensorarrow_forwardDefine or state the principle of operation, draw the wiring diagram, discuss the construction and application of each motor Split phase capacitor motor Repulsion motorarrow_forwardRefer to the circuit shown in Figure 105. Assume that the motor is running and an overload occurs, which causes the OL contact to open and disconnect coil M to stop the motor. What effect does the opening of the overload contact have on the pressure switch circuit?arrow_forward
- Q3/ Chose the correct answer for the following 1. Synchronous motors are generally not self-starting because (a) the direction of rotation is not fixed (b) the direction of instantaneous torque reverses after half cycle (c) startes cannot be used on these machines (d) starting winding is not provided on the machines 2. The power developed by a synchronous motor will be maximum when the load angle is (a) Zero (b) 45° (c) 90° (d) 120° 3. An over-excited synchronous motor takes (a) leading current (b) lagging current (c) both (a) and (b) (d) none of the above 4. In a synchronous motor, the magnitude of stator back e.m.f. £& depends on (a) d.c. excitation only (b) speed of the motor (c) load on the motor (d) both the speed and rotor flux 5. A pony motor is basically a (a) small induction motor (c) D.C. shunt motor (b) D.C. series motor (d) double winding A.C./D.C. motorarrow_forward1. It is a machine that converts mechanical energy to electrical energy. 2. It is a machine that converts electrical energy to mechanical energy. 3. It is cylindrical or drum-shaped where the coils are placed and can either be lap wounded or wave wounded. 4. It connects the commutator to the other parts of the DC machine. 5. It serves as the housing of the dc machine. 6. True or False: The shunt field winding is part of the armature. 7. True or False: The long shunt compound generator is when the armature is in series with the series field winding and parallel to the shunt field winding. 8-10. Your newly built house needs an elevator. Which from the following will be best to use- series, shunt or compound motor and why?arrow_forward23. When the circuit breaker is always tripping, most likely There is an overloading c. The supply line are open a. b. There is an over current d. The load is removed 24. The synchronous motor is not inherently self- starting because the rotating magnetic field does not have enough poles b. the rotating magnetic field is produced by only 50 HZ frequency currents the force required to accelerate the rotor is to the synchronous speed in an instant is d. the starting devices to accelerate the rotor to near synchronous speed is absent 25. Synchronous motor has speed a. slight drop in speed on full load b.high speed at low torque а. с. c. constant speed d. low speed at high -arrow_forward
- For the Starting Up the Power Station Simulator Why are certain operations blocked by isolatorsarrow_forwardyou are working as a plant electrician. you are told that a large DC motor was returned from the rewind shop and was installed on the previous shift. the motor seemed to operate properly until load was added, the motor then stopped, reversed direction, and began to run at a high speed. what is the probable cause of the trouble, and what would you do to correct the problem?arrow_forwardWrite general information about sequential timer for DC motor controlarrow_forward
- Describe how pressure switches are connected to start and stop (a) small motors and (b) large motors.arrow_forwardThere are 2 1000Watt 3-phase asynchronous motors in a Walnut Cracking machine (it is desirable to operate the motors in a way that they remain in star connection). When the "Start" button is pressed, the 1st engine will start immediately, 3 seconds after the 1st engine starts, the 2nd engine will also start. After the two engines work together for 4 seconds, the 1st engine will stop, the 2nd engine will start and stop for another 10 seconds. If the "Stop" button is pressed at any stage of the operations, the motors will stop. The rotation directions of the motors are required to be opposite to each other. Draw the necessary power and control circuit.(EKTS )arrow_forwardThere are 2 1000Watt 3-phase asynchronous motors in a Walnut Cracking machine (it is desirable to operate the motors in a way that they remain in star connection). When the "Start" button is pressed, the 1st engine will start immediately, 3 seconds after the 1st engine starts, the 2nd engine will also start. After the two engines work together for 4 seconds, the 1st engine will stop, the 2nd engine will start and stop for another 10 seconds. If the "Stop" button is pressed at any stage of the operations, the motors will stop. The rotation directions of the motors are required to be opposite to each other. Draw the necessary power and control circuit.arrow_forward
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