C390S - Monodirectional Drive

The 390S drive was designed to control the speed of Rowan high slip motors (S series) equipped with tachometrical dynamo. It is a threephase current adjuster with tachometric backfeed which uses controlled diodes (SCR) piloted by the system with thyristore for phase control. The voltage which pilots the motor comes from an analogue process which keeps the revolutions constant by means of differential control between the real speed reference extracted by the tachometrical dynamo and the speed set by the potentiometer or external analogue voltage.

When combined with a Rowan threephase high slip motor, the result is a fast system with constant couple that is extremely quiet and uniform, from zero to maximum motor revolutions. The choice of the controlled diodes for the power part (already overdimensioned) guarantees reliability in the case of extra voltages or extra currents. The rotational direction of the motor is selected by exchanging 2 phases of either the supply card or the motor itself, as is done with standard threephase asynchronous motors (to check the rotational direction with a +10VDC signal use the 380S type bidirectional drive).

It is also possible to adjust the acceleration and deceleration ramps according to the needs of the device moved by the Rowan threephase motor. Dc braking (which is also valid for low inertia loads or limited braking needs) starts automatically if the ramp time of deceleration ramps with inertial loads is not respected. If the contrary is necessary, a 380S type twoway drive should be installed.

With the 390S drive it is possible to carry out combined couple-revolution control of the Rowan threephase motor, which can, consequently, work as an electromagnetic brake or gear. Because of this, the combination of a 390S drive and a Rowan high slip motor could be used with excellent results in moving winders/ unwinders.