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Hi,
I have been struggling with a question for the past two days and can not get where the problem is:
Assume a multiple anchor coils DC Motor with the following dimensions:
Length - L_r=50[mm]
Diameter - D_r=30[mm]
Stator electric field - B=1[T]
Single winding resistance - 50[mOhm]
Number of windings - n=17
V_in=11[V]
1. What is the maximum power of the motor [W]?
For this part I calculated the Omega_max and Tau_max :
Omega_max=V_in*1/K_Omega --> 11/(1*17*0.05*0.03)=431.37[Rad/s]
Tau_max=I_max*K_Tau --> (11/(0.05*17))*(1*17*0.05*0.03)= 0.33[NM]
Power=Omega_max*Tau_max=142.35[W]
2. With the data above I am supposed to do a LTSPICE simulation and build the Omega(Tau), Power(Tau) and Efficiency(Tau) graphs.
There are 2 things I am not sure about that I can not solve -
a. If I multiply the "i(Bemf)" value with {Km} (meaning - "I=i(Bemf)*{Km}") I get negative value at the V(RPM) graph thus getting an opposite Omega-Tau graph. Only when I do it as the picture above I get the right results, very very close to the calculated values. I am not sure if my calculations are wrong or the Simulation.
b. I export the Omega-Tau data to excel, calculate the Omega*Tau and create the power graph but the result I get is a scale bigger than the calculated result; Instead of 142.35[W] I get about 1420[W] as the maximum value of the power.
I am not sure what am I doing wrong here and seeing how I already went through all the lectures but can not make this work hope to get some help here.
Thank you!
I have been struggling with a question for the past two days and can not get where the problem is:
Assume a multiple anchor coils DC Motor with the following dimensions:
Length - L_r=50[mm]
Diameter - D_r=30[mm]
Stator electric field - B=1[T]
Single winding resistance - 50[mOhm]
Number of windings - n=17
V_in=11[V]
1. What is the maximum power of the motor [W]?
For this part I calculated the Omega_max and Tau_max :
Omega_max=V_in*1/K_Omega --> 11/(1*17*0.05*0.03)=431.37[Rad/s]
Tau_max=I_max*K_Tau --> (11/(0.05*17))*(1*17*0.05*0.03)= 0.33[NM]
Power=Omega_max*Tau_max=142.35[W]
2. With the data above I am supposed to do a LTSPICE simulation and build the Omega(Tau), Power(Tau) and Efficiency(Tau) graphs.
There are 2 things I am not sure about that I can not solve -
a. If I multiply the "i(Bemf)" value with {Km} (meaning - "I=i(Bemf)*{Km}") I get negative value at the V(RPM) graph thus getting an opposite Omega-Tau graph. Only when I do it as the picture above I get the right results, very very close to the calculated values. I am not sure if my calculations are wrong or the Simulation.
b. I export the Omega-Tau data to excel, calculate the Omega*Tau and create the power graph but the result I get is a scale bigger than the calculated result; Instead of 142.35[W] I get about 1420[W] as the maximum value of the power.
I am not sure what am I doing wrong here and seeing how I already went through all the lectures but can not make this work hope to get some help here.
Thank you!
