OSAI digital drives

Where flexibility, speed and accuracy of machine tool control is required, the preferred choice of CNC controller is often Osai. Now, the perfect partner for Osai CNC - and other CNC controllers too - is available in the UK.

The Osai digital DAC servodrives and DSC spindle drives and motors are specifically designed for machine-tool application and give outstanding position, speed and torque accuracy, with the added feature of numerical control using high-speed optic-fibre connectivity.

The DAC range of axis drives utilises state-of-the-art digital technology for the control of permanent magnet DC servomotors. Two sizes of module are presently available, covering powers of 4.5 kW and up to 18 kW. In addition to the traditional analogue ± 10 V input for controlling speed or torque, DAC drives provide a SERCOS digital interface for communication with the numerical control system by means of a high-speed optic fibre. The digital interface ensures greater immunity to noise and a higher capacity for real-time data exchange with the NC system. The main user benefits are enhanced finished product accuracy, because of the faster communication, and optimised machine tool cycle times.

The machine tool supplier also benefits from the reduced cost of cabling and much easier set-up and testing of the machine.

The perfect partners for the DAC drives are the zero maintenance DS brushless synchronous motors, which incorporate rare-earth permanent magnets for maximum power output in a very compact package. With torque from 0.4 to 57 Nm and speeds up to 6000 rpm, DA motors have very low rotor inertia for an outstanding dynamic performance with a peak torque of at least three times the rated value. Being powered at 540 VDC, currents and hence heat, is minimised.

The DSC digital vector control drives are particularly suitable for controlling 3-phase asynchronous motors in spindle applications. The regenerative braking as standard, the drives are available in a modular or single block configuration, depending on the power controlled and are capable of controlling spindles with power requirements of up to 70 kW.

The DA asynchronous motors, designed specially for spindle duty, span the range 1.8 to 22 kW for application speeds of 1500 to 8000 rpm.

Users benefit further from the digital controller module that is universal for all DAC and DSC drives. The controller can receive position, torque and speed commands via RS232 serial, analogue or SERCOS inputs. Current and speed loops are monitored every 62.5 microseconds, giving superb motor control. What's more, the controller supports Windows set-up, which provides a graphic display of the block diagram of the regulating system and of the parameters.

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