Industrial Motor Control
7th Edition
ISBN: 9781133691808
Author: Stephen Herman
Publisher: Cengage Learning
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Chapter 46, Problem 4RQ
What solid-state device is generally used to produce variable frequency in drives designed to control motors up to 500 horsepower?
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Design a complete belt drive system for an AC motor (NT) running a fan 12 hrs/day, with an input power 10 hp and
input speed of 1000 RPM. The desired output RPM and center distances are 500 RPM and 36 inch, respectively
In speed coontrol of dc motor, the final control element is motor.
Select one:
O True
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Assume that you are to design a 3V V-belt drive. Given that input speed as 1750 rpm and nominal output speed as 725 rpm. Starting with belt linear velocity 4000 ft/min, specify the input sheeve D1 from the list above.
D1 = ___ in.
Provide write down steps including equations
Chapter 46 Solutions
Industrial Motor Control
Ch. 46 - Prob. 1RQCh. 46 - Prob. 2RQCh. 46 - If an alternator is used to provide variable...Ch. 46 - What solid-state device is generally used to...Ch. 46 - Why are SCRs used to construct a bridge rectifier...Ch. 46 - What is the main disadvantage of using SCRs in a...Ch. 46 - How are junction transistors driven into...Ch. 46 - What is the disadvantage of driving a junction...Ch. 46 - Prob. 9RQCh. 46 - In variable frequency drives that employ IGBTs,...
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- Why are SCRs used to construct a bridge rectifier in many solid-state variable frequency drives?arrow_forwardQUESTION 8 Consider the equations of motion of an armature controlled DC motor given by Jw(t)+bw (t) Ki(t) = -Tfriction - Tload (t) di (t) + Ri (t) + Kw (t) = Vin (t), dt where vin(t) is the input voltage and Tload(t) is the input load torque. The outputs are the armature current i(t) and the motor speed w(t). The steady-state response of motors are specified by nominal voltage, stall torque, stall current, no load speed, and no load current. At steady-state operation, the motor equations satisfy bo) -Ki =-T -T. fric load Ri +Kov_- 55 55 The stall torque is the load torque required stead-state speed of the motor is zero. The stall current is the armature current when the motor speed is zero. The no load speed is the speed of motor when the load torque is zero. The no load current is the current when the load torque is zero. What is stall torque for this motor in N-m? Keep 3 significant figures, and do not include units. Use Scientific notation. The constants are given below. Nominal…arrow_forwardA 7460 W split-phase motor running at 1750 rpm is used to drive a rotary pump. The pump should run continuously at approximately 1175 rpm. The center distance should not exceed 1118 mm. Space limits the diameter of the driven pulley to 292 mm. Determine: a. the pulley diameters, b. the belt size, and c. the number of belt required.arrow_forward
- Problem 1 3-Phase AC Machinery Principles Part 1: Complete the following table by calculating the speed of magnetic field rotation in AC machines depending on the number of poles and the operating frequency. Number of Speed (RPM) Poles Frequency f = 50 Hz Frequency f= 60 Hz 4 6. 10 Solutionarrow_forwardA 50 Hz pump drive requires a torque of 70 Nm approx. at 1450 rpm approx. for 1 minute followed by 5 minutes running unloaded. This cyclic pattern is repeated continuously. The motor is to be selected from a range of general-purpose motors with continuous ratings of 2.2, 3, 4, 5.5, 7.5, 11, 15 and 20 kW. The motors have a pull-out torque of 200%. 1. Select the pole number. 2. Calculate the continuous power rating. 3. 4. Calculate the required power rating given the pull out torque rating. Estimate the slip when the motor drives the pump at the required speed. Choose the motor from the range of options that is most fit for purpose. 5. Enter your answers in the units indicated (without unit symbols) corrected if necessary to two decimal places. Answer: Number of poles= ✓ Continuous power rating (kW)= Required power rating for 200% pull out torque (kW)= Percentage slip (%) = Most suitable motor from given range (kW)-arrow_forwardThe figure below shows an electromechanics system that is consist of a DC motor controlled by a servo amplifier, and lead screw via a worm gear. The lead screw extends and contracts to drive a mass. DC Motor Worm Gear and Lead Screw Motor Servoamplifierarrow_forward
- The 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_forwarda 7460 w split-phase motor running at 1750 rpm is used to drive a rotary pump. the pump should run continuously at approximately 1175 rpm. the center distance should not exceed 1118 mm. space limits the diameter of the driven pulley to 292 mm. design a. the pulley diameters, b. the belt size, and c. the number of belt required.arrow_forwardAs shown in the figure below, this is a speed regulation method for DC separately excited motor. a) What is the speed regulation method? b) What are the characteristics for this speed regulation method? B no Ra le lo R: '3 E R3 Tr. Tarrow_forward
- 2-14 The current in a 60 Hz single-phase motor lags 36 degrees behind the voltage. Calculate the time interval between the posi- tive peaks of voltage and current.arrow_forwardAssume that you are to design a 3V V-belt drive. Given that input speed as 1750 rpm and nominal output speed as 725 rpm. Starting with belt linear velocity 4000 ft/min, specify the input sheeve D1 from the list above. D1 = ___ in. Provide write down steps including equations. *** 8.73 and 8.9 were marked incorrectarrow_forwardA drive has the following parametersMotor torque: T=150 –0.1N, N-m where N is the speed in rpm.Load torque: TL=100, N-m.Initially the drive is operating in steady state. The characteristics of the loadtorque are changed to TL =-100 Nm.(i) Calculate the initial and final equilibrium speeds.(ii) Can a motor load system with a passive load torque have an equilibrium speedin quadrant II ? What will be your answer if the load is active?arrow_forward
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