Drives and Controls Magazine

Digital servo amp is `a major advance`

01 February, 2002

Digital servo amp is `a major advance`

The US motion control specialist Copley Controls has developed a digital servo amplifier which it is hailing as "a major advance in motor drive technology". The Accelus amplifier uses field-oriented control - a strategy that maintains a 90-degree displacement between the rotor and stator magnetic fields at all speeds - to allow motors to deliver a higher torque, speed and efficiency for a given drive current.

Copley says that the amplifier`s high efficiency allows smaller motors to be used for a given task, while the low motor and amplifier heat output means that, in many applications, convection cooling will be sufficient.

The amplifier provides sinusoidal commutation, resulting in ripple-free-drive torque, reduced vibration, and the avoidance of marred surfaces in cutting and polishing applications, the company adds. The amplifier has been designed to work with a variety of controllers and to accept different signal inputs. This will allow brushless servomotors to replace steppers and brushed servos in many applications, Copley suggests.

A built-in algorithm monitors the heating effect of the load current, allowing the motor to be operated safely at maximum performance. The amplifier can deliver 300% of continuous current as a peak, allowing the motor to be accelerated rapidly. This is expected to be particularly useful in robotic applications where it will minimise positioning time.

The amplifier is designed to be used with Copley`s Motion Explore 2 software which is said to allow systems to be commissioned with a single mouse click. There are two models: one runs on 20-90V supplies, delivering 3A continuously and 9A as a peak; the other, for 20-50V supplies, provides 6A continuous and 18A peak.