Product category:
Drives, motors and power transmission, couplings, clutches
News Release from: Inmoco | Subject: Kolmorgen ServoDisc motors
Edited by the Manufacturingtalk Editorial
Team on 24 June 2003
Ironless disc armature servos are more
compact
Machine designers and automation engineers requiring more performance from servo motors, whilse seeking to reduce size should consider products with ironless disc armatures.
Machine designers and automation engineers requiring more performance from their servo motors, whilst at the same time seeking to reduce size and improve installation flexibility, should consider the unique Kolmorgen range of ServoDisc motors, now available in the UK from Inmoco Unlike conventional DC servos, Kolmorgen ServoDisc motors have an ironless disc armature, which enables them to achieve higher levels of performance than conventional servomotor designs in both incremental motion and continuous speed applications
This article was originally published on Manufacturingtalk on 19 Apr 2001 at 8.00am (UK)
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The ServoDisc design is highly efficient as a result of avoiding the losses associated with conventional iron armature servomotors.
These losses increase with speed, so as a conventional motor goes faster, it uses more of its available torque just to keep itself turning.
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Consequently, less torque is left to deliver to the output shaft.
In many applications this torque "drop-off" means that the next higher size of motor has to be selected to guarantee sufficient torque at high speed.
As ServoDisc motors do not have these iron-associated losses, they do not suffer from this problem and are able to deliver more torque over their entire speed range.
In fact, the torque is almost constant right across the speed range from 0 to 4000 rpm.
Not only is the torque constant with the ServoDisc design, it is also delivered fast.
The low inductance of the motors provides a low electrical time constant, which is a measure of how long it takes for current to flow into the armature of the motor.
For ServoDisc motors this constant is less than one millisecond, a figure that ensures full torque almost instantaneously, and the key to fast movement and accurate tracking.
The ServoDisc architecture is also superior in applications where temporary levels of peak torque are required, as in the case of rapid acceleration and deceleration.
A peak current is applied to the motor to produce this torque.
In iron core motors the magnitude of this current is generally limited to 2-3 times the continuous current rating, to prevent demagnetizing of the motor magnets.
With the non-magnetic ServoDisc armature and axial magnetic field, this problem is virtually eliminated, enabling most ServoDisc motors to be rated for 10 times the continuous current rating.
Complementing the superior torque performance of the ServoDisc motors is the exceptional levels of acceleration they provide.
Designed with a low inertia armature, a typical ServoDisc motor can accelerate from 0 to 3000 rpm in only 60 degrees of rotation.
Such levels of response mean that, in some applications, entire moves can be performed in less than 10 milliseconds.
For the end user this means shorter cycle times, higher throughput and, crucially, higher productivity and improved profitability.
The overall performance benefits of ServoDisc motors mean that they are not only first choice for general servo tasks, but also for critical applications where torque disturbances, or "cogging" is a problem.
The ServoDisc armature, being ironless, is not attracted by magnets, as is the case with conventional servomotors.
The result is zero "cogging", and ultra-smooth rotation at any speed.
An additional benefit of there being no iron in the ServoDisc construction is that there is little or no induction, and no arcing as a result.
This is important, as arcing, not friction is the major cause of brush wear.
The elimination of arcing leads to very long brush life in most applications.
In fact, depending on the application, it is possible for the brushes to last as long as the bearings.
The removal of arcing as a problem also means that there are no commutation limits with ServoDisc units due to speed, the motors being able to operate at speeds up to 4,000rpm and above.
Inmoco is offering the benefits of ServoDisc technology across a wide range of package sizes and power levels.
Motors are presently available with torques from 0.07Nm to 27Nm and power outputs from 30 watts to 4.5 kilowatts.
This means that there is a product match for nearly every application.
Intelligent Motion Control has over 30 years experience in the servo drive industry.
Inmoco's products are used in Robots, Machine Tools, Automation, Metal Bending, Handling, Packing, Textiles and Paper (etc.).
They are backed- up by comprehensive application and service facilities. Request a free brochure from Inmoco ...
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