Control Systems and Utilization
Control Systems and Utilization combines control fundamentals with illumination, electric heating, welding and traction. The paper tests transfer functions, stability and practical utilization calculations.
Control fundamentals
- A transfer function is the Laplace ratio of output to input with zero initial conditions.
- Poles are roots of the denominator; poles in the right half-plane indicate instability.
- Routh–Hurwitz checks stability without solving the characteristic equation.
- PID control uses proportional, integral and derivative actions; integral action removes steady-state error.
Utilization
- Illumination: luminous flux is measured in lumens, illuminance in lux (lumens per square metre).
- Electric heating includes resistance, induction and dielectric heating; welding includes arc and resistance welding.
- Traction: tractive effort depends on adhesive weight and adhesion coefficient; DC series motors are historically suited to traction because of high starting torque.
Worked example
A workshop of 100 m² is lit by 20 lamps of 2000 lm each. Utilization factor is 0.5 and maintenance factor is 0.8. Illuminance E = (N × Φ × CU × MF)/A = (20 × 2000 × 0.5 × 0.8)/100 = 160 lux.
Traps that cost marks
Confusing lumens with lux, ignoring the maintenance factor, and placing a closed-loop pole in the right half-plane are common. In traction, do not confuse tractive effort with power; power equals tractive effort times speed. In PID, derivative action improves transient response but amplifies noise.