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B.VIGNESH Edited By Sarath S Nair technologyfuturae

Series Wound DC Motor Modeling and Simulation, Considering Magnetic, Mechanical and Electric Power Losses. B.VIGNESH Edited By Sarath S Nair www.technologyfuturae.com. Contents. Introduction DC Series motor ideal model Series wound DC motor losses Mechnical losses Magnetic losses

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B.VIGNESH Edited By Sarath S Nair technologyfuturae

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

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

  4. Diagram of DC series motor (dotted line showing electrical, mechanical and magnetic component) www.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+k2i2(τ)]) www.technologyfuturae.com

  6. Armature current ia(τ)=ea/(R+kω(τ)) • Torque T(τ)=kia2(τ) • Mechanical power Pm(τ)= ω ( τ)*T(τ) • Electrical power Pe(τ)=ea*ia(τ) www.technologyfuturae.com

  7. Power loss Pp(τ)=Pe(τ)-Pm(τ) • Efficiency η (τ)=Pm(τ)/Pe(τ) www.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 www.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 PRC=0.52dglg√(Vg3 ) • Diameter dg=2.84√(Pm/n) • Length lg=2.5dg • Peripheral speed Vg=(∏.n.dg)/6000 www.technologyfuturae.com

  10. If the machine has rolling bearings PRC =150(dg)3n 10-6 • the result is multiplied by the number of bearings PRC= nc.PRC • Brush friction power losses PRE PRE=9.81µePSeVcol • Peripheral speed Vcol=(∏.Dcol.n)/6000 • Brushes surface friction Se=∑Brushes surface www.technologyfuturae.com

  11. Ventilation Losses Pv=1.1 V VV2 • 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 PMR=PRC+PRE+PV www.technologyfuturae.com

  12. Magnetic power loss • Eddy current losses Pf(t)=w2[ea]2/(12ρ (NA)2 ) www.technologyfuturae.com

  13. Electrical power losses • Armature copper loss • Pcu=R ia2 www.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= ρα20˚C[1+ α [T-20˚C]] • Therefore • R(τ)= ρ L/A =L/A ρα20˚C[1+ α [T-20˚C]] www.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+k2i2(t)]) • Electricalcurrent ia(τ)=ea/(R(τ)+kω(t)) • Power losses Pf(t)= w2[e(f)]2 /(12 ρα20˚C[1+ α [T-20˚C]] (NA)2 ) • Copper losses Pcu=R(τ) ia2(τ) www.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. www.technologyfuturae.com

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

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

  19. Brush friction power loss www.technologyfuturae.com

  20. Ventilation power loss www.technologyfuturae.com

  21. Eddy current power loss www.technologyfuturae.com

  22. Electrical power loss www.technologyfuturae.com

  23. Temperature fluctuation www.technologyfuturae.com

  24. Armature resistance fluctuation www.technologyfuturae.com

  25. Torque vs angular speed www.technologyfuturae.com

  26. Torque vs electric current www.technologyfuturae.com

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

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

  31. THANK YOU www.technologyfuturae.com

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