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Direct Drive Rotary Motors

            Conventional servo systems commonly have a mechanical transmission which                                                  Which DDR Product is Right for Your Application?
            can consist of gears, gearboxes, belts/pulleys or cams connected between
            the motor and the load. With Direct Drive Rotary Motors, the mechanical   Gearbox Gearbox                                 Kollmorgen’s 70 years of electromagnetic and electromechanical design experience combined with our quality and service,
            transmission is eliminated and the motor is coupled directly to the load.                                                 allowed us to refine and expand DDR motors into three product categories for easy installation, use, and short lead times:
                                                                                     Servo   Servo
                                                                                    Motor  Motor                                      Frameless DDR, Housed DDR, and the Cartridge DDR. This allows you to select the right DDR solution for your application.
            Why Use Direct Drive Rotary Motors?                                             Servo Motor and Gearbox

            Increased Accuracy and Repeatability                                                    F    F
                                                                                               r    r
            A “precision” planetary gearbox could have a backlash of 1 arc-minute. This can result in
            the load moving by 1 arc-minute with an absolutely stationary drive motor. Kollmorgen’s                                                     Applications where the load rides on the motor’s bearings such as indexing or rate tables
            standard direct drive rotary (DDR) servo motors have repeatability better than 1 arc-second.   Direct Drive
   O MO
            Therefore, a direct drive motor can hold a position 60 times better than a conventional                                                                   Cartridge DDR
            motor/gearbox.                                                                                                                                            This motor is the first in the industry to combine the space-saving and performance advantages of
            The increased accuracy of direct drive rotary motors results in a higher quality product out of                                                           Frameless DDR motors with the ease of installation of a full-frame motor. Consisting of a rotor, stator, and
            the machine:                                                                                                                                              factory-aligned high-resolution feedback device, the motor uses the machine’s bearings to support the
              • Print registration is more accurate                             Improved   1        Gearbox                                                           rotor. An innovative compression coupling engages the rotor to the load and the frame of the motor mounts
              • Cut or feed lengths can be held more precisely                 Repeatability                                                                          to the machine with a bolt circle and pilot diameter just like a conventional servo motor, saving space and
              • Coordination with other machine axes is more accurate                    Arc                                                                          design time and simplifying the overall system.
              • Indexing location is more exact                                         Minutes 0     DDR
              • Tuning issues due to backlash are eliminated                                          60 Times Better
            Higher Bandwidth
            Mechanical transmission components impose a limit on how fast a machine can start and                                        Any application with existing bearings
            stop and also extend the required settling time. These factors limit the possible throughput   Conventional Rotary
            of a machine.                                                                        Servo with Mechanical                   Housed DDR
            Direct drive rotary motors remove these limitations and allows for much faster start/  Increased Throughput
            stop cycles and also provide greatly reduced settling time. Machine users of direct drive   DDR motors                       The Housed DDR is a housed motor assembly featuring a factory aligned high-resolution feedback
   Y MO
            systems have reported up to a 2X increase in throughput.                             – higher throughput                     device and precision bearings, allowing it to function as the core of rotary indexing and rate
                                                                                                 – no start/stop limitations
                                                                                                                                         table applications. The system can also be used as a flexible indexer, providing programmable,
            Improved Reliability and Zero Maintenance                                                                                    rapid indexing far exceeding the throughput and accuracy of conventional mechanical or variable
            Gears, belts, and other mechanical transmission parts break. By eliminating these parts and using DDR motors, the reliability of the machine is improved.   reluctance indexers.
            Gearboxes require periodic lubrication and/or replacement in aggressive start/stop applications. Belts require periodic tightening. There are no time-wear
            components in a direct drive motor and consequently they require zero maintenance.
            Fewer Parts
            With direct drive motors, all you need is the motor and the mounting bolts. This often replaces many parts including brackets, guards, belts, pulleys,   Applications where size and weight must be absolutely minimized
            tensioners, couplings, and bolts, resulting in:
              • Fewer parts on the BOM. Less parts to purchase, schedule, inventory and control, and less parts to assemble.                                                     Frameless DDR
              • Assembly time of the servo drops from several hours with the mechanical transmission to several minutes with the DDR.
              • Reduced cost. Although a direct drive motor may carry a small price-premium compared to a motor/gearbox with the same torque, consider that there is             Frameless motors include a rotor and stator as separate components which are
               an overall cost reduction when eliminating the parts and labor of all the extra components required in a servo system with mechanical transmission.               integrated into, ride on the bearings of, and become a part of the driven load. Frameless
                                                                                                                                                                                 motors offer the most compact and lightweight DDR solution available. The KBM  and
            No Inertia Matching                                                                                                                                                  TBM series are Kollmorgen’s Frameless DDR products. The KBM provides excellent
                                                                                                                                                                                 torque/volume with the use of a proprietary neodymium-iron magnet rotor structure and
            Servo systems with mechanical transmissions require inertia matching that limits the reflected load inertia at 5 to 10 times the motor inertia. If this limitation
            is not met, the system becomes difficult to control due to instability issues. Inertia matching limitations of mechanical transmission systems often force           skewed armature assembly. The KBM series is the first UL recognized parts set available
            machine designers to use a larger motor than would otherwise be required just to satisfy the inertia matching requirement.                                           on the market. This provides OEMs with the benefits of UL component ratings for easier
                                                                                                                                                                                 agency approval on their machines. The TBM frameless motor is a series of direct
            Such sizing conventions are not required with direct drive rotary motors. Since the motor is directly connected to the load, the inertia of the motor and the load   drive torque motors designed for applications that require high power in a small,
            become a common inertia. Therefore, no inertia matching is required when using DDR. DDR applications have run with inertia ratios greater than 11,000:1.
                                                                                                                                                                                 compact form factor with minimized weight and inertia.
            Reduced Audible Noise
            Machines with DDR motors have audible noise levels as low as 20 dB less than the same machine with a mechanical transmission.

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