Electric Motor Control
10th Edition
ISBN: 9781133702818
Author: Herman
Publisher: CENGAGE L
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Chapter 44, Problem 4SQ
To determine
Find the series resistance required to limit the current to 30 A across a
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Students have asked these similar questions
1 - Why is a starting resistor needed to bring a motor up to speed?
How to avoid the effect of the high current at starting of the Motor?
a.
variable resistor is connected in series with Armature circuit
b.
variable resistor is connected in parallel with Armature circuit
c.
variable resistor is connected in series with field circuit
d.
None of the above
Clear my choice
If the full load current of a three-phase motor is 40 Amperes, the size of the circuit breaker is
a. 100 AT c. 300AT
b. 120 AT d. 80 AT
A 50-hp, 440-volt, 3-phase, 1750 rpm, SCRIM, how many pair of poles
a. 4 c. 3
b. 2 d. 1
The required rated voltage applied to a six leads out motor are
a. 760-volts and 440-volts c. 440-volts and 254-volts
b. 220-volts and 127-volts d. All of the above
Chapter 44 Solutions
Electric Motor Control
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Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, electrical-engineering and related others by exploring similar questions and additional content below.Similar questions
- In Figure 327, the motor cannot be started in high speed. Why?arrow_forwardA squirrel-cage induction motor has a nameplate full-load current of 78 amperes and a marked temperature rise of 30C. The motor requires a NEMA size 4 starter. Using the overload heater chart in Figure 34-8, what size overload heaters should be used to protect this motor?arrow_forwardMotors will operate satisfactorily at what percent over and under voltage?arrow_forward
- you 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_forwardA forward-reverse motor starter must be prevented from form reversing while running in the forward rotation. What is done? a. install electrical limit switches b. install electrical interlocking c. install a NC stop button d. install a NO pushbutton.arrow_forwardThe starting current of a 15-hp, 440 volt, and three-phase induction motor is 32 amperes when rated voltage is applied. What voltage should be applied at the starting instant if the starting current is not to exceed 60 amperes?arrow_forward
- A 240-volt shunt motor takes 5 amperes on no-load. The armature resistance is 0.25 ohm and the field resistance is 200 ohms. Calculate the efficiency when taking full load current of 50 amperes and the percentage change in speed between no-load and full-load.arrow_forwardWhat might be a hazard if a motor is started in the wrong direction?arrow_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
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