public class Vent extends Appliance {
    private float maxPower = 90.0f;
    private float rpm = 0.0f;
    private final float rotorInertia = 7.0f;
    private final float maxRPM = 6500.0f;

    public Vent(boolean plugged) {
        super(plugged);
    }

    public void step(float seconds) {
        // electric current usage
        if (super.getPowerState()) {
            rpm += max(min(((int) (maxRPM - rpm) * rotorInertia), maxPower), 0)
                * 10 / rotorInertia * seconds;
        }
        
        // air drag (always present)
        rpm -= (rpm / 200) / rotorInertia;
    }

    public float getPowerConsumption() {
        if (super.getPowerState()) {
            return max(min(rotorInertia*(maxRPM - rpm), maxPower), 0);
        } else {
            return 0f;
        }
    }

    public float getRPM() {
        return rpm;
    }
}