Abstract: An improved control system for controlling the position of an upper electrode in a carbon arc lamp. The system has a pulley with a line thereover, and a solenoid core is attached to one end of the line and is movable vertically in a solenoid coil connected in the circuit for supplying discharge current to the electrodes, and a control rod clutch is connected to the other end of the line which normally grasps and holds an electrode control rod on the lower end of which is mounted the upper electrode of the lamp. A balancing weight is provided on the core to balance the weight of the control rod clutch and electrode and a shield is provided around the solenoid coil to shield the arc between the electrodes from the magnetic field of the solenoid coil.