Understanding Motor Controls
4th Edition
ISBN: 9781337798686
Author: Stephen L. Herman
Publisher: Delmar Cengage Learning
expand_more
expand_more
format_list_bulleted
Concept explainers
Question
Chapter 35, Problem 8RQ
To determine
Whether the output voltage of the electro-tachometer increases or decreases when the speed of the motor decreases.
Expert Solution & Answer
Trending nowThis is a popular solution!
Students have asked these similar questions
Recall that the CWH equation involves two important assumptions. Let us investigate how these
assumptions affect the accuracy of state trajectories under the control inputs optimized in (a) and (b).
(c.1): Discuss the assumptions about the chief and deputy orbits that are necessary for deriving CWH.
PROBLEM 2.50
1.8 m
The concrete post (E-25 GPa and a
=
9.9 x 10°/°C) is reinforced with six
steel bars, each of 22-mm diameter (E, = 200 GPa and a, = 11.7 x 10°/°C).
Determine the normal stresses induced in the steel and in the concrete by a
temperature rise of 35°C.
6c
"
0.391 MPa
240 mm
240 mm
6₁ =
-9.47 MPa
For some viscoelastic polymers that are subjected to stress relaxation tests, the stress decays with
time according to
a(t) = a(0) exp(-4)
(15.10)
where σ(t) and o(0) represent the time-dependent and initial (i.e., time = 0) stresses, respectively, and t and T denote
elapsed time and the relaxation time, respectively; T is a time-independent constant characteristic of the material. A
specimen of a viscoelastic polymer whose stress relaxation obeys Equation 15.10 was suddenly pulled in tension to
a measured strain of 0.5; the stress necessary to maintain this constant strain was measured as a function of time.
Determine E (10) for this material if the initial stress level was 3.5 MPa (500 psi), which dropped to 0.5 MPa (70
psi) after 30 s.
Chapter 35 Solutions
Understanding Motor Controls
Ch. 35 - Prob. 1RQCh. 35 - Why is this component used instead of a diode?Ch. 35 - What is a freewheeling or kickback diode?Ch. 35 - Name two methods of sensing the current flow...Ch. 35 - Prob. 5RQCh. 35 - What unit controls the voltage applied to the...Ch. 35 - What device is often used to sense motor speed?
Ch. 35 - Prob. 8RQ
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, mechanical-engineering and related others by exploring similar questions and additional content below.Similar questions
- For the flows in Examples 11.1 and 11.2, calculate the magnitudes of the Δ V2 / 2 terms omitted in B.E., and compare these with the magnitude of the ℱ terms.arrow_forwardCalculate ℛP.M. in Example 11.2.arrow_forwardQuestion 22: The superheated steam powers a steam turbine for the production of electrical power. The steam expands in the turbine and at an intermediate expansion pressure (0.1 MPa) a fraction is extracted for a regeneration process in a surface regenerator. The turbine has an efficiency of 90%. It is requested: Define the Power Plant Schematic Analyze the steam power system considering the steam generator system in the attached figure Determine the electrical power generated and the thermal efficiency of the plant Perform an analysis on the power generated and thermal efficiency considering a variation in the steam fractions removed for regeneration ##Data: The steam generator uses biomass from coconut shells to produce 4.5 tons/h of superheated steam; The feedwater returns to the condenser at a temperature of 45°C (point A); Monitoring of the operating conditions in the steam generator indicates that the products of combustion leave the system (point B) at a temperature of 500°C;…arrow_forward
- This is an old practice exam question.arrow_forwardSteam enters the high-pressure turbine of a steam power plant that operates on the ideal reheat Rankine cycle at 700 psia and 900°F and leaves as saturated vapor. Steam is then reheated to 800°F before it expands to a pressure of 1 psia. Heat is transferred to the steam in the boiler at a rate of 6 × 104 Btu/s. Steam is cooled in the condenser by the cooling water from a nearby river, which enters the condenser at 45°F. Use steam tables. NOTE: This is a multi-part question. Once an answer is submitted, you will be unable to return to this part. Determine the pressure at which reheating takes place. Use steam tables. Find: The reheat pressure is psia. (P4)Find thermal efficiencyFind m dotarrow_forwardAir at T1 = 24°C, p1 = 1 bar, 50% relative humidity enters an insulated chamber operating at steady state with a mass flow rate of 3 kg/min and mixes with a saturated moist air stream entering at T2 = 7°C, p2 = 1 bar. A single mixed stream exits at T3 = 17°C, p3 = 1 bar. Neglect kinetic and potential energy effects Determine mass flow rate of the moist air entering at state 2, in kg/min Determine the relative humidity of the exiting stream. Determine the rate of entropy production, in kJ/min.Karrow_forward
- Air at T1 = 24°C, p1 = 1 bar, 50% relative humidity enters an insulated chamber operating at steady state with a mass flow rate of 3 kg/min and mixes with a saturated moist air stream entering at T2 = 7°C, p2 = 1 bar. A single mixed stream exits at T3 = 17°C, p3 = 1 bar. Neglect kinetic and potential energy effects Determine mass flow rate of the moist air entering at state 2, in kg/min Determine the relative humidity of the exiting stream. Determine the rate of entropy production, in kJ/min.Karrow_forwardAir at T1 = 24°C, p1 = 1 bar, 50% relative humidity enters an insulated chamber operating at steady state with a mass flow rate of 3 kg/min and mixes with a saturated moist air stream entering at T2 = 7°C, p2 = 1 bar. A single mixed stream exits at T3 = 17°C, p3 = 1 bar. Neglect kinetic and potential energy effects (a) Determine mass flow rate of the moist air entering at state 2, in kg/min (b) Determine the relative humidity of the exiting stream. (c) Determine the rate of entropy production, in kJ/min.Karrow_forwardA simple ideal Brayton cycle operates with air with minimum and maximum temperatures of 27°C and 727°C. It is designed so that the maximum cycle pressure is 2000 kPa and the minimum cycle pressure is 100 kPa. The isentropic efficiencies of the turbine and compressor are 91% and 80%, respectively, and there is a 50 kPa pressure drop across the combustion chamber. Determine the net work produced per unit mass of air each time this cycle is executed and the cycle’s thermal efficiency. Use constant specific heats at room temperature. The properties of air at room temperature are cp = 1.005 kJ/kg·K and k = 1.4. The fluid flow through the cycle is in a clockwise direction from point 1 to 4. Heat Q sub in is given to a component between points 2 and 3 of the cycle. Heat Q sub out is given out by a component between points 1 and 4. An arrow from the turbine labeled as W sub net points to the right. The net work produced per unit mass of air is kJ/kg. The thermal efficiency is %.arrow_forward
- Steam enters the high-pressure turbine of a steam power plant that operates on the ideal reheat Rankine cycle at 700 psia and 900°F and leaves as saturated vapor. Steam is then reheated to 800°F before it expands to a pressure of 1 psia. Heat is transferred to the steam in the boiler at a rate of 6 × 104 Btu/s. Steam is cooled in the condenser by the cooling water from a nearby river, which enters the condenser at 45°F. Use steam tables. NOTE: This is a multi-part question. Once an answer is submitted, you will be unable to return to this part. Determine the pressure at which reheating takes place. Use steam tables. The reheat pressure is psia.Find thermal efficieny Find m dotarrow_forwardThis is an old exam practice question.arrow_forwardAs shown in the figure below, moist air at T₁ = 36°C, 1 bar, and 35% relative humidity enters a heat exchanger operating at steady state with a volumetric flow rate of 10 m³/min and is cooled at constant pressure to 22°C. Ignoring kinetic and potential energy effects, determine: (a) the dew point temperature at the inlet, in °C. (b) the mass flow rate of moist air at the exit, in kg/min. (c) the relative humidity at the exit. (d) the rate of heat transfer from the moist air stream, in kW. (AV)1, T1 P₁ = 1 bar 11 = 35% 120 T₂=22°C P2 = 1 bararrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Understanding Motor ControlsMechanical EngineeringISBN:9781337798686Author:Stephen L. HermanPublisher:Delmar Cengage Learning
Electrical Transformers and Rotating MachinesMechanical EngineeringISBN:9781305494817Author:Stephen L. HermanPublisher:Cengage Learning
Automotive Technology: A Systems Approach (MindTa...Mechanical EngineeringISBN:9781133612315Author:Jack Erjavec, Rob ThompsonPublisher:Cengage Learning
Welding: Principles and Applications (MindTap Cou...Mechanical EngineeringISBN:9781305494695Author:Larry JeffusPublisher:Cengage Learning
Refrigeration and Air Conditioning Technology (Mi...Mechanical EngineeringISBN:9781305578296Author:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill JohnsonPublisher:Cengage Learning
Automotive TechnologyMechanical EngineeringISBN:9781337794213Author:ERJAVEC, Jack.Publisher:Cengage,
Understanding Motor Controls
Mechanical Engineering
ISBN:9781337798686
Author:Stephen L. Herman
Publisher:Delmar Cengage Learning
Electrical Transformers and Rotating Machines
Mechanical Engineering
ISBN:9781305494817
Author:Stephen L. Herman
Publisher:Cengage Learning
Automotive Technology: A Systems Approach (MindTa...
Mechanical Engineering
ISBN:9781133612315
Author:Jack Erjavec, Rob Thompson
Publisher:Cengage Learning
Welding: Principles and Applications (MindTap Cou...
Mechanical Engineering
ISBN:9781305494695
Author:Larry Jeffus
Publisher:Cengage Learning
Refrigeration and Air Conditioning Technology (Mi...
Mechanical Engineering
ISBN:9781305578296
Author:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill Johnson
Publisher:Cengage Learning
Automotive Technology
Mechanical Engineering
ISBN:9781337794213
Author:ERJAVEC, Jack.
Publisher:Cengage,