Abstract: An apparatus having a drive pulley around which the wire is rolled, driven by a motor coupled to a speed control element. The pulley is provided with a tachometer which generates a signal proportional to the speed of movement of the wire. An extensometer, coupled to the wire, generates a signal, representative of a predetermined, ideal tension in the wire, which is compared with a set value. The resulting signal is superimposed on the tachometer signal to generate a signal to control the control element. The apparatus may also be provided with a spring biased oscillating arm located after the extensometer that has a pulley on one end, over which the wire passes. Also, a coding wheel may be provided after the oscillating arm assembly which generates a signal proportional to the speed of the wire. The coding wheel signal is converted to a signal representative of a variation in tension of the wire.