Assignment 5

1.) Objective:

Implement DC machine torque speed characteristics equations in MATLAB script file and

yield a plot of speed (RPM) versus torque (Nm).

In order top solve this problem, a brushed DC motor is taken into consideration which has

the characteristic equation as follows:

T = [(V – ω*K)*K]/R_a,

Where, T – Motor torque in N-m,

V - Supply Voltage in volts,

ω – Angular speed in rad/sec,

K – Motor torque constant in N-m/A,

R_a – Armature resistance in ohms.

The Matlab code to calculate the Motor torque and to plot speed vs torque graph is shown

below:

1.	Objective:

Implement DC machine torque speed characteristics equations in MATLAB script file and 

yield a plot of speed (RPM) versus torque (Nm).

In order top solve this problem, a brushed DC motor is taken into consideration which has 

the characteristic equation as follows:

                         T = [(V – ω*K)*K]/R_a,

Where,            T – Motor torque in N-m,
                          V - Supply Voltage in volts,
                          ω – Angular speed in rad/sec,
                          K – Motor torque constant in N-m/A,
                          R_a – Armature resistance in ohms.

The Matlab code to calculate the Motor torque and to plot speed vs torque graph is shown 

below:

Result:

Conclusion:

It can be seen from the graph that the plot is a linear decay which means that the Motor 

torque is inversely proportional to the speed of the motor.

Result:

Conclusion:

It can be seen from the graph that the plot is a linear decay which means that the Motor

torque is inversely proportional to the speed of the motor.

2.) The distinction between power cables and signal cables used in EV’s are delineated as

Follows:

POWER CABLES	SIGNAL CABLES
1. As its name indicates, it is mainly used for the purpose of power transmission.	Signals cables are intended to give response and warning signals to the driver.
2. In terms of construction, it is an assemblage of more than 1 cable.	Signal cables are generally single cable which carries information to the driver.
3. These are high power and high current rated.	These are low power and low current rated.
4. It is mainly comprised of Conductor, insulator and protective sheath.	It is made up of a conductor and a transparent jacket.
5. Power cables are expensive.	Signal cables are cheap.

3.) In order to comprehend the capacity of a battery, we need to check something called

as nominal voltage of the battery.

Nominal voltage of a battery can be defined as the average voltage a battery outputs when

fully charged. In reality, the actual voltage will be slightly higher than the nominal voltage.

For instance, almost all modern EV’s make use of Lithium based batteries whose nominal

Voltage range is around 3.6V per cell. If the voltage falls below this level, it is said to be low

Voltage and if the voltage rises above this level it is said to be high voltage. Usually when in

driving mode the voltage level will be above the nominal voltage due to regeneration from

generator/alternator.