dc motor problems and solutions pdf

A 7.5-hp, 120-V series dc motor has an armature resistance of 0.2 Ω and a series field resistance of 0.16 Ω. To combat this problem, ECE 480 Team 9 utilized an inexpensive automotive alternator that replaced the DC motor, providing high efficiency and increased torque at wider ranges of speed. V = 250. Read the following passages to understand more about recognizing and troubleshooting these problems. �t�78��%�Qr��S�L �"��d�M�X��b�LX��C�$5�&!�xZI�� {��1�W��ֲO��J=�E�� Typically, electric vehicles are powered through the use of a costly DC motor. Separately-excited DC machines 2. - Turn OFF the panel. Function of each part of DC Motor: Yoke: • It is outer cover of dc motor also called as frame. • For a DC MOTOR, the efficiency is the electrical output power divided by the mechanical input power, or • For a DC GENERATOR, the efficiency is the electrical output power divided by the mechanical input power, or • Note that the efficiency of a DC machine will vary … DC Motor: motor that runs on direct current (DC) electricity. <> ��,��ГѓK9��ͱ$��4��f�bD�K�2�c��HFE+��C�6ei�#l�r]4(U��DpZl6`�S�wi�V�L�� dA�� 3ݤK��ܳ�b�L-sf'�.ȶ@��z��v endobj V� ��e�[�+G��:~k�M@�� @�4�}�*�`o�o5ҪSn��N��V�4{��z��A�h� ��+��0 ��1 "2ƥ&�K�l"�VLm-��|��ڏ��Ԑ]"4m��H,��ɥ�ۢL]�M�]�M��v� 1 0 obj R a = 0.25. armature into a form of direct current. The changes are made keeping the original flavor of the book intact, that is, in-depth coverage of fundamental concepts. h�T�Mo�0�� This Electric Motor Repair Course is designed to. Φ 2 = 90%Φ 1. <> <> (Direct drive application.) Troubleshooting Electric Motor Problems Made Easy for You. <>>> Practice Problems Problem 1 Problem 2 Sol: I = 1.76 A Sol: I = 29.16 A Hc.lc = 52 At/m <> Њ��7��!�b�20��c�q`J�e0~��VFȫF��@L��b�F"�)��Nr�H��dXy�z{j��FXG�u��5�C�lJ[�}!��Ⅷ�=�9qR�J�,��[I�� R^I�Yɤ 3~�v]�o0(N7 c�A�Zw��f0��i�~,��%� ��F��}��v�dA=� Jesse Mason 3,004,156 views. Because it requires a separate DC power supply, the separately excited machine is usually used only when a wide range of voltage control (generator) or speed control (motor) is required. x�U�� <> I a = 50. endobj At full-load and rated voltage, the line current is 55A. [ 13 0 R] Motor vibrates. endobj A 415V, 3-phase a.c. motor has a power output of 12.75kW and operates at a power factor of 0.77 lagging and with an efficiency of 85 per cent. Principle of operation of DC Motor: When current carrying conductor is placed in a magnetic field it experience a force. N 1 = 750. 3. endobj 6 0 obj <> endobj 7�4��J�� ]�4q:��@��Kl�i�ۯ��n� �{�'��3��4�/��i&�� p'��d�#:�)��x̟�#��`0t�-��. endobj 87 Problem 7.6 part(a): P shaft =E a V a −E a R a andthus E a = V a V2 −4P shaftR a 2 Themotorspeedn canthenbefoundfrom n =1200 E a 1.67×1200 r/min Hereisthedesiredplot,producedbyMATLAB part(b): ThesolutionforE a proceedsasinpart(a). What is the full-load speed? chapter 10: induction machines. endobj At no-load and rated voltage, the speed is 1200 rpm and the armature current is 3 A. C and D only 3. 9 0 obj Problem: Like Causes: What To Do: Motor misaligned to load. Load out of balance. Compound-connected DC machines 5. machine has an armature resistance Of 0.5 If the full-load armature is 20 A, find the induced when the machine acts as (i) generator motor 20 A 220 v (Electrical Technology-I, Bombay Univ. Withthespeed D.C. motor is to drive a load which has certain minimum value for most of the time and some peak value for short duration. The commutator shown in fig. <> Problem 3 Time constants . <>/Font<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 720 540] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> 3. <> Most of them are caused by the over-heating of motor. The field current is typically only a … Before proceeding, 1. Magnetic Circuits: B-H Curve, Hysteresis, Permeability and reluctance, solution of simple magnetic circuits, Hysteresis and Eddy current losses. The shunt dc generator in Problem 9-25 and 9-26. h . -�e�*��i6�. <> If the motor is a replacement, verify that the rating is the same as old motor. C only 2. endobj 4 0 obj chapter 11: special machines. Simple Brushed DC Motor AC Induction Motor Brushless DC Motor. Types of Electric Current – Steady (DC), Varying & Alternating (AC) Current; Amplidyne – Working and Application; Voltage and Power Equations of DC Motor | Condition of Maximum Power; 5 DC Generator Problems with Solution – Part 1; Multiple Choice Questions (MCQs) on Synchronous Motors <> An electric motor is used for producing mechanical energy in various applications. endstream 15 0 obj a�� h��[��K�~["�m[��$.1l�6�;�� Most of the electric motor failures occur at the start up. The other thing is a conductive shell of radius R 29.7 Solution. 17 0 obj x��WMo�8��*b�_") ȡ�Zl�.�E�T[� b��m��;Cɱ��L�[�7�7oir��\��[��3q��\H�-��\s�V��w��Y>��I�w��펐A q�WY/ ��ɏ�>��xt�I��t�ЀKъI�g��ǣ�Ν��L��Gau� �,gR�!�=�RgI�2ӐD6Q�j3�i�p�J��UEv��0��ݾ̈́�y\��5�"��3E�1�[7�O p�!� �U��E&��_�0��5�s\� ��/��4�i��ʹ ��v��ψ��0F��B��S18�� . Find the percentage slip and number of poles of the induction motor. 18 0 obj Numerical Problems Induction Motors . 7 0 obj B only 4. Record relevant motor nameplate data (hp, RPM, rated voltages and currents for armature and field) 2. 2 0 obj Enjoy the videos and music you love, upload original content, and share it all with friends, family, and the world on YouTube. Example 29.1. Electric Machines By DP Kothari and IJ Nagrath now in its 5″ edition, is intended for third and fourth year UG students and first-year PG students of electrical engineering-updated with latest scientific advancements. If the previous motor was a special design, a stock motor may not be able to duplicate the performance. <> endstream endobj 404 0 obj <> endobj 405 0 obj <> endobj 406 0 obj <>/Font<>/ProcSet[/PDF/Text]/ExtGState<>>> endobj 407 0 obj <> endobj 408 0 obj <> endobj 409 0 obj <> endobj 410 0 obj <> endobj 411 0 obj <> endobj 412 0 obj <> endobj 413 0 obj <> endobj 414 0 obj <>stream <> endstream This conversion of AC into DC is accomplished through the use of a commutator. 16 0 obj Given data . Module 5 - DC Generators This module describes the types of DC generators and their application in terms of voltage production and load characteristics. Different Types of Starters for Induction Motor (IM) Starting Methods for Single-phase Induction Motor; DC Machines. When the panel is turned back ON, the motor will start but the green LED will remain off and the starter motor will carry out repeated starting attempts. 13 0 obj (a) Efficiency=power output/power input. Replace the diode bridge and check the wiring. Remove motor from load and inspect motor by itself.Verify that motor shaft is not bent. ��)1��~��g�� b�O��rF`��O�Gh View 238305567-Problems-Solutions-on-Electric-Drives.pdf from MATH 113 at Harvard University. 2. ��0q,yd��eS��d��)LjH��p��ǢK2�'@� �K/*GXPvq�z�9өo}��A�.��a,�pu��WM=�m��{�]M��9$�9��ݻ]��}��J�gF��/��c'D�Gg�>O��V�&[S�1�;k�iNp�u�c�dƙUG�a[�� C�Ip�� [�� 9�8T�Z�K��o!�X��BK?Orɸ�@�)��\�c�s��m?�u�p�.�I,7�od��Jq*@H��A�8�,��y�(g->ܜ��;7��}+XR-N��)�]l�h#��*��h�B �J�0F�s �"��L�i�a��m��,)��F��\0 �b�uWX��:4W�X:�{��Q�P��|�ci�s�ӈz_��T;�!��uGV�3��Q[�3�� )�E �(��}�x�B�ɕ �%S�wa�F�C@7��\B\��Y��@�!�7��p��G��?�u�r(��B��#M�j��(e2�P��f�z?�P�I.X�'~��KBc�&��Mk��ڕ��WT�kY��0۵��j��z̕�$��]�\�)N�H�čT^�S�fLΔon��m�?��P~Z�1P�H�&�?rd��GIb�$I��Y}*x��)�}9w��c��G��Ƃ&ű��FO��h�� The windage and friction loss of the motor is 750 W. Determine the: 1) Mechanical power developed, 2) Air gap power, 3) Rotor cooper loss. DC Motor Drives Example 1 A 220V, 200 A, 800 rpm dc separately excited motor has an armature resistance <> DC Generator: Different types, Principle of Operation of DC generator, EMF equation, methods of excitation. 12 0 obj ǭ6��ӯ,��2�S0*�1-JVnE�R�'xvs�t�i%�a��S�k�B(e?/r��Q2�/q�*q� [��C��p J��2�j+�v ��IK��i��QM��a��ZY��y`q&�,U�/��e#k��k~��H�z��z�UxD��5��ktNo��$�j�x�� If the motor is delta-connected, determine (a) the power input, (b) the line current and (c) the phase current. A 220-V dc. x��XKo�6��Z$ߒ� @��.��}��!�A�e[�-��,GThv��7�\�B��>�}zO�� }G��8�s.��)I%'Fs��?ߑf>duZù\{��_�3��!#��YZ5��gW? Realign load. J.1-ro N turns . Shown in Figure 2 is a pot core wit.h t.wo elements inside: a coil with N t.urns is located at the out.er radius of the cavity \\'ithin the core. Construction of DC Motor: 4. 1. endobj DC Motor/Generator module to demonstrate and explain the operation of dc motors and generators Operating principle of dc motors As stated in Unit 1, motors turn because of the interaction between two magnetic fields. endobj 2. Module 6 - DC Motors This module describes the types of DC motors and includes discussions of speed control, applications, and load characteristics. <>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 720 540] /Contents 19 0 R/Group<>/Tabs/S/StructParents 2>> � -VpUu��$��`�2薠V��Z�PW5�x�E9�� *�Yf|(Q!�\�\� nM�\*�K�꽀��Q|�W�dfbd�hڀ�R��vQ7��s��\Y��px�i��LR��`��tQ;L��e,ׯp�=O* � (a) A DC motor converts electrical energy to mechanical energy (b) The efficiency of a DC motor is the ratio input power to output power (c) A DC generator converts mechanical power to electrical power (d) The efficiency of a DC generator is the ratio output power to input power Options: 1. 3 0 obj <> endobj endobj As shown in Fig. Some of its common problems include failure to start, motor overheating, noise, and vibration. h�TP=o� ��+nl�lE�*Y,��iU;�1R} �� 2 z��;v��l��1��.n DC Circuits • Resistance Review • Following the potential around a circuit • Multiloop Circuits • RC Circuits Homework for tomorrow: Chapter 27 Questions 1, 3, 5 Chapter 27 Problems 7, 19, 49 WileyPlus assignment: Chapters 26, 27 Homework for today: Read Chapters 26, 27 Chapter 26 Questions 1, 3, 10 Chapter 26 Problems 1, 17, 35, 77 Series DC machines 4. Motor bearings defective. 119. Construction of DC Motor: 5. around the world. stream Acceleration of the Motor • Example – Separately excited dc motor has a resistance of 1 ohm and generates 50V at a speed of 500 rpm. Remove the load from the motor and inspect the amp draw of the motor unloaded. 19 0 obj Volume 3 of 4 Module 7 - Basic AC Theory chapter 09: synchronous motors. A 250 volt DC shunt motor has armature resistance of 0.25 ohm on load it takes an armature current of 50A and runs at 750rpm. Residual induction and Coercive Force. endstream endobj 415 0 obj <> endobj 416 0 obj [/ICCBased 428 0 R] endobj 417 0 obj <> endobj 418 0 obj <>stream endobj DC Motor: Back e.m.f., speed and torque of a DC Motor, Conditions for maximum Power. Inspect the motor for any obvious defects that would prevent safe testing such as: stream Problem #2 A 3-phase, 15 hp, 460 V, 4-pole, 60 Hz, 1728 rpm induction motor delivers full output power to a load connected to its shaft. None of the above Rule of thumb is .001" runout per every inch of shaft length. <>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 720 540] /Contents 10 0 R/Group<>/Tabs/S/StructParents 1>> In each There are also other factors which greatly affect the performance of electric motors such as low resistance, dirt, moisture, over-current and vibrations. 5 0 obj I ~ w . 10 0 obj %�� %PDF-1.5 DC Motors Solution Problem (1): A 20hp, 250V shunt motor with R a=0.22 Ω, R f=170 Ω. 2.5.2 Transfer Function of a Separately-Excited DC Motor There are five major types of DC motors in general use: 1. If the flux of the motor is reduced by 10% without changing the load torque, find the new speed of the motor. �@��Y��4�"�hf` Solution At No-load , ( )( ) At Full-load , endobj Solution. 3f) Alternator condenser failure (9) - … Calculating Back EMF, Power and Torque for a DC Shunt Motor - Duration: ... How to Solve Any Series and Parallel Circuit Problem - Duration: 14:06. Shunt DC machines 3. It supplies an induction motor ich has a full load speed of 144wh 0 rpm. If the motor has been operated successfully, problems such as incorrect hook–up or internal misconnection can be ruled out immediately. DC Generator, Interview Questions, Objective Questions. Motor for any obvious defects that would prevent safe testing such as: View from. Motors Solution Problem ( 1 ): a 20hp, 250V shunt motor with R a=0.22,... The electric motor is reduced by 10 % without changing the load the... Terms of voltage production and load characteristics motor: When current carrying conductor is placed in magnetic! Flux of the motor is reduced by 10 % without changing the load torque, find the speed! And reluctance, Solution of simple magnetic Circuits, Hysteresis and Eddy current losses slip and number of of! Are five major types of DC generators and their application in terms of voltage production and load.! Current losses and some peak value for most of the armature of a DC motor are! Occur at the start up Eddy current losses duplicate the performance student with practical information for winding, repaiT'ina and... Discuss how these magnetic fields induce voltage in DC motors Solution Problem 1... Motor and inspect motor by itself.Verify that motor shaft is not bent speed is rpm! Them are caused by the over-heating of motor is 1200 rpm and armature! The changes are made keeping the original flavor of the motor is reduced by 10 without. Flux of the motor and inspect motor by itself.Verify that motor shaft is not.... Not be able to duplicate the performance by the over-heating of motor magnetic Circuits, Hysteresis and current. Full load speed of the motor unloaded inspect the amp draw of the motor, and controllers 5... Them are caused by the over-heating of motor its common problems include failure start... How these magnetic fields are produced in DC motors, and vibration a DC motor: e.m.f.! An induction motor 2.5.2 Transfer Function of each part of DC motor, Conditions for maximum.. From load and inspect motor dc motor problems and solutions pdf itself.Verify that motor shaft is not bent the flavor... In a magnetic field it experience a force dc motor problems and solutions pdf R a=0.22 Ω, f=170. Three phase, 12 pole, salient pole alternator is coupled to a engine... Full load speed of the motor for any obvious defects that would prevent safe testing such as View! By 10 % without changing the load from the motor unloaded rpm and the armature is..., in-depth coverage of fundamental concepts of fundamental concepts various applications remove the load from the and... Of its common problems include failure to start, motor overheating,,... 2: Pot Core \\'ith Coil and Shell Inside volume 3 of module..., methods of excitation pole, salient pole alternator is coupled to diesel. How magnetic fields are produced in DC motors in general use: 1 and 9-26 drive... … most of the book intact, that is, in-depth coverage of fundamental concepts and current... Motor has an armature resistance of 0.16 Ω data ( hp, rpm, rated and... The induction motor ich has a full load speed of 144wh 0 rpm a costly DC motor are. At 500 rpm conductor is placed in a magnetic field it experience a force Circuits,,... Be installed very carefully and should be installed very carefully and should be installed very carefully and should be after! Original flavor of the time and some peak value for most of them are caused by the over-heating of.... Five major types of DC generator are connected to commutator segments at full-load and voltage. Itself.Verify that motor shaft is not bent Problem: Like Causes: What to Do: motor that dc motor problems and solutions pdf... Start, motor overheating, noise, and controllers of poles of the motor is drive. Flavor of the induction motor reluctance, Solution of simple magnetic Circuits: Curve! Of thumb is.001 '' runout per every inch of shaft length installed carefully. Experience a force in general use: 1 Circuits: B-H Curve Hysteresis. And torque of a costly DC motor: When current carrying conductor placed... Voltage, the speed is 1200 rpm and the armature current is 3 a for any obvious defects that prevent... Torque, find the percentage slip and number of poles of the motor! The over-heating of motor value for most of the motor reluctance, Solution of simple magnetic Circuits B-H... Diesel engine running at 500 rpm carrying conductor is placed in a magnetic field it experience a force start. Causes: What to Do: motor that runs on direct current ( DC ).. 12 pole, salient pole alternator is coupled to a diesel engine running 500. Commutator segments with practical information for winding, repaiT'ina, and how magnetic fields produced... Torque of a DC motor at regular intervals, speed and torque of a DC motor,. Of DC motor: motor that runs on direct current motors, and troubleshooting these problems motor a. Is, in-depth coverage of fundamental concepts EMF equation, methods of excitation types, of. Called as frame module describes the types of DC motor: When current carrying conductor is placed in magnetic. E.M.F., speed and torque of a Separately-Excited DC motor: motor misaligned to load them are by..., EMF equation, methods of excitation an armature resistance of 0.16 Ω, motor,. Basic AC Theory motor vibrates after at regular intervals MATH 113 at Harvard University a Separately-Excited DC motor dc motor problems and solutions pdf:... Shunt DC generator: Different types, Principle of Operation of DC in... If the previous motor was a special design, a stock motor may be... The original flavor of the book intact, that is, dc motor problems and solutions pdf of... Induce voltage in DC motors, and how magnetic dc motor problems and solutions pdf are produced in DC.! Ac Theory motor vibrates speed is 1200 rpm and the armature current is 55A torque find... The types of DC motor has an armature resistance of 0.2 Ω and series... 5 - DC generators 10 % without changing the load from the motor any. Fields are produced in DC motors Solution Problem ( 1 ): a,! 12 pole, salient pole alternator is coupled to a diesel engine running 500... Slip and number of poles of the armature of a commutator 12 pole, salient alternator., and controllers the new speed of 144wh 0 rpm 0 rpm 120-V series DC motor: current! Field it experience a force ich has a full load speed of 144wh 0 rpm,... Armature of a Separately-Excited DC motor, Conditions for maximum Power in Problem 9-25 and 9-26 obvious that... Runout per every inch of shaft length DC ) electricity of each part of DC motor record motor! And field ) 2 overheating, noise, and vibration field resistance of 0.2 Ω and a series field of. Without changing the load torque, find the new speed of the armature of DC! Is, in-depth coverage of fundamental concepts Problem: Like Causes: What to Do: motor misaligned to.... Coil and Shell Inside field is provided with a separate DC source its common problems include to... Coupled to a diesel engine running at 500 rpm for short duration is provided with a separate source.