Electric Motor Control
10th Edition
ISBN: 9781133702818
Author: Herman
Publisher: CENGAGE L
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Chapter 49, Problem 5SQ
To determine
Explain which contacts are closed in Figure 49-4 when full voltage is received by a brake coil.
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Electric Motor Control
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- Refer to the basic control schematic in Figure 344. The limit switch is shown as a. normally open. b. normally closed. c. normally open held closed. d. normally closed held open. Fig. 344 Wiring diagram of manual speed regulator interlocked with magnetic starter for control of slip ring motor (three-wire control).arrow_forwardIn Figure 362, how many different interlocking conditions exist? Name them. Fig. 362 Typical elementary diagram of a starter with two points of acceleration for a reversing wound rotor motor.arrow_forwardA starter turns very slowly and has excessive cranking current draw. When removed from the vehicle and bench tested, the starter spins normally and current draw is within specifications. Technician A says poor battery connections may be the cause. Technician B says an internal engine problem may be the cause. Who is correct?arrow_forward
- Determine the minimum current for conductors required to connect a motor that has a full-load current of 46 A.arrow_forwardAccording to the stator terms of a 3-phase Star connected 380 V, 5 Hp 50 H, 4-pole 1450 rpm induction motor, Rs= 0.3 ohm, Xs=0.5 ohm, R2= 0.15 ohm, X2=0.3 ohm. The idling power of the motor is 400 W. By drawing the equivalent circuit of the motor, find the power and efficiency taken from the motor when it is running at 1% slip and under full load.arrow_forwardQ.30 How many amperes does a 1-horsepower, 240-volt, single-phase motor draw? Select one: A. 8 AMPERES B. 4.7 AMPERES C. 4.2 AMPERES D. 8.8 AMPERESarrow_forward
- Why is it necessary to remove the jumpers in Figure 362 if limit switches are used? FIG. 362 Typical elementary diagram of a starter with two points of acceleration for a reversing wound rotor motor.arrow_forwardTwo shunt generators and a battery are all connected to common bus-bars. The open circuit voltage of the battery is 247 V. The open circuit voltage, armature and field resistances of the generators are 250 v, 0.12 ohms and 100 ohms respectively. Both the generators supply the same current when the load on the bus-bars is 40 A. Calculate the internal resistance of the batteryarrow_forwardA belt-driven 202 Hp shunt wound DC generator is running at 465 rpm and issupplying full load to a bus bar at 232 V. At what speed will it run if the belt breaksand the machine continue to run taking 9 kW from the bus bar? The armature andthe field resistances are 0.05 Ohm and 100 Ohms respectively. The brush contactdrop is 2 Volts per brush.arrow_forward
- Determine the no. of studs and resistance of the section for a D.C. series motor starter from data: 6 kW, 415 V D.C. series motor, starting current varies from 1.4 to 2 times full load current, flux increases 15% for variation of current from minimum to maximum, motor resistance 1.7 Ω motor efficiency 80%.arrow_forward8.a. Which of the following most accurately describes the difference between a contactor and a starter?A. A starter contains a contactor and some additional protective circuitry.B. A starter is always mounted in an enclosure.C. A starter contains reversing contacts.D. A starter is always three-phase while a contactor may be single-phase or three-phase.8.b. The main bus in a motor control center is used toA. reduce the possibility of overload with large loads.B. enclose motors within a protective shield.C. distribute power to all starters in the center.D. reduce the voltage of the plant's supply.arrow_forwarda). If it is known that the total traction force in the Bung Tomo circuit is 231.9N, what is the required motor torque if the radius of the wheel is 0.2475 m?arrow_forward
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