Part (a) A constant flux DC machine can be represented by the following equations: Va Raia + La Tektia = dia dt +e e = kewm Te = TL + Bwm + J dwm dt Assume ke = kt Write the state space equations and draw a state space diagram representing the dynamics of a constant flux dc motor. [8 marks] G sT+1 Part (b) A dc drive as described in part (a), with the load torque T = 0, has an armature current control loop which is tuned to give a first order lag response, as given in the equation below: ia(s) Draw a block diagram of a speed control system which uses the above current controller. [6 marks] Part (c) wm(s) Assuming that the speed controller in part (b) is proportional only, write the closed-loop transfer function of the speed control system. wm (s) [6 marks] Part (d) Apply the steady-state condition on the transfer function you derived in part (c) and derive an expression for the steady-state speed error in terms of the reference speed wm. [10 marks]