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Series Wound DC Motor Modeling and Simulation, Considering Magnetic, Mechanical and Electric Power Losses B.VIGNESH Edited By Sarath S Nair www.technologyfuturae.com.

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Presentation on theme: "Series Wound DC Motor Modeling and Simulation, Considering Magnetic, Mechanical and Electric Power Losses B.VIGNESH Edited By Sarath S Nair www.technologyfuturae.com."— Presentation transcript:

1 Series Wound DC Motor Modeling and Simulation, Considering Magnetic, Mechanical and Electric Power Losses B.VIGNESH Edited By Sarath S Nair www.technologyfuturae.com 1

2 Contents Introduction DC Series motor ideal model Series wound DC motor losses Mechnical losses Magnetic losses Electrical losses Additional losses Conclusion References 2www.technologyfuturae.com

3 Introduction There are three types of DC motors: shunt wound DC motor, series wound DC motors, compound wound DC motor. Has relatively high starting torques Has good accelerating torque Have low speed at high loads and high speed at low loads Under same load conditions rating of series motor will be less than for a shunt motor 3www.technologyfuturae.com

4 Diagram of DC series motor (dotted line showing electrical, mechanical and magnetic component) 4www.technologyfuturae.com

5 SERIES WOUND DC MOTOR IDEAL MODEL here there are no disturbances of any kind are examined the power losses through the input and output power. Hence we obtain the following equation Angular velocity ω( τ )= (ξ.k.i( τ ).ea+RJ ω( τ - ξ))/ (RJ+ ξ [Rb+k 2 i 2 ( τ )]) 5www.technologyfuturae.com

6 Armature current ia(τ)=ea/(R+kω(τ)) Torque T(τ)=ki a 2 ( τ ) Mechanical power Pm(τ)= ω ( τ)*T(τ) Electrical power Pe(τ)=ea*ia(τ) 6www.technologyfuturae.com

7 Power loss Pp(τ)=Pe(τ)-Pm(τ) Efficiency η (τ)=Pm(τ)/Pe(τ) 7www.technologyfuturae.com

8 SERIES WOUND DC MOTOR LOSSES Within the DC motor components energy is exchanged between different sections in these exchange, there are power losses. Mechanical losses Magnetic losses Electrical losses 8www.technologyfuturae.com

9 Mechanical losses the mechanical losses are found in surfaces in contact and constant friction 1.Friction losses in the slip bearings These losses are due to continuous friction P RC =0.52d g l g √(V g 3 ) Diameter dg=2.84√(Pm/n) Length lg=2.5dg Peripheral speed Vg=(∏.n.dg)/6000 9www.technologyfuturae.com

10 If the machine has rolling bearings P RC =150(d g ) 3 n 10 -6 the result is multiplied by the number of bearings P RC= n c.P RC Brush friction power losses PRE P RE =9.81µ e PS e V col Peripheral speed Vcol=(∏.Dcol.n)/6000 Brushes surface friction Se=∑Brushes surface 10www.technologyfuturae.com

11 Ventilation Losses P v =1.1 V V V 2 Cooling of motor is determined by V=∑losses transformed into heat/1000te The fan speed given by Vv=(∏.Dv.n)/6000 Mechanical losses of the machine P MR =P RC +P RE +P V 11www.technologyfuturae.com

12 Magnetic power loss Eddy current losses P f (t)=w 2 [ea] 2 /(12ρ (NA) 2 ) 12www.technologyfuturae.com

13 Electrical power losses Armature copper loss P cu =R i a 2 13www.technologyfuturae.com

14 Additional losses In an electric machine there are areas in continuous friction that can contribute to heat emission either by exposing to a long working time and / or by excessive load The wire conductor resistance R= ρL/A The resistivity is given by ρ= ρ α20˚C [1+ α [T-20˚C]] Therefore R( τ )= ρ L/A =L/A ρ α20˚C [1+ α [T-20˚C]] 14www.technologyfuturae.com

15 In developing the mathematical model, there are equations where the resistance and resistivity of the material occurs. Then the following equations are rewritten: ω(t)= (ξ.k.i(t).ea+R( τ )J ω( τ - ξ))/(R( τ )J+ ξ [R( τ )b+k 2 i 2 (t)]) Electrical current ia(τ)=ea/(R(τ)+kω(t)) Power losses P f (t)= w 2 [e(f)] 2 /(12 ρ α20˚C [1+ α [T-20˚C]] (NA) 2 ) Copper losses P cu =R( τ ) i a 2 ( τ ) 15www.technologyfuturae.com

16 GENERALIZATION OF A SERIES WOUND DC MOTOR In this section there is a more complete analysis, and random noises are added aside from considering to the model, considering also the internal losses. 16www.technologyfuturae.com

17 Angular velocity with deterministic and no deterministic disturbances 17www.technologyfuturae.com

18 Friction power losses in the slip bearings 18www.technologyfuturae.com

19 Brush friction power loss 19www.technologyfuturae.com

20 Ventilation power loss 20www.technologyfuturae.com

21 Eddy current power loss 21www.technologyfuturae.com

22 Electrical power loss 22www.technologyfuturae.com

23 Temperature fluctuation 23www.technologyfuturae.com

24 Armature resistance fluctuation 24www.technologyfuturae.com

25 Torque vs angular speed 25www.technologyfuturae.com

26 Torque vs electric current 26www.technologyfuturae.com

27 Angular speed vs electric current 27www.technologyfuturae.com

28 Conclusion By including the powers losses in the series wound DC motor simulation in addition to the disturbances a series of graphs were obtained which give broader information of the possible behaviour of the system 28www.technologyfuturae.com

29 References J. S. Valdez Martínez, P. Guevara López, J. J. Medel Juárez. Series Wound DC Motor Modeling and Simulation, Considering Magnetic, Mechanical and Electric Power Losses. Sept.09 B.L.Theraja.A.K.Theraja.A Textbook Electrical Technology.S.Chand and Company ltd. 29www.technologyfuturae.com

30 Log On to www.technologyfuturae.com Technical Presentations, Research Reviews, New designs & Developments

31 THANK YOU 31www.technologyfuturae.com


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