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Motor Specifications

Featured throughout this catalog are motion and manipulation instruments which are suitable for motorization. Motorization options for specific instruments are listed on the page in which they appear. Specifications for each motor option are identified with a single letter code ("A" through "F") listed as “Motor Spec” in the options description table. Detailed specifications for each motor are listed in this section and are arranged alphabetically by letter code.

Alternating Current Motors

MDC reversible AC motors are an economical motorization solution for continuous motion applications. These motors are equipped with a load limiting clutch rated for 50 oz-in of torque to prevent instrument overload conditions. Motors come with three wire leads and a capacitor which must be wired by the customer to suit application circuit requirements. Motor direction reversal is accomplished by wiring reversal. Current applied to the blue and red leads produces a clockwise rotation while applying current to the blue and black leads produces counterclockwise rotation.

Direct Current Motors, Analog

MDC 90 volt direct current reversible motors are of the permanent magnet type featuring high efficiency, no field supply requirement, low heat and linear speed-torque characteristics. Two leads with integral connector provide easy mating with 90 volt motor controller. These motors are furnished with an integral gear unit with 180:1 gear reduction. The gearing is of the helical-spur design with helical gears in the primary stage for quiet operation and hardened spur gears in the secondary stages. Mounting dimensions conform to NEMA 2-11 standards.

Miniature DC Motors

Miniature DC motors are used on all MDC motorized miniature rotary and linear motion instruments. The built in gear head with a 262:1 gear ratio gives this motor a maximum torque load of 20 oz-in. Devices fitted with these miniature motors are constructed with a load limiting clutch to prevent motor burnout. Motors are mounted to motion instruments inside anodized aluminum housings with inline or side mount drive geometries. Inline geometries can also be purchased with a 16 pulse per revolution magnetic encoder.

DC Stepper Motors

Stepper motors are devices which position loads by operating in discrete increments or steps. The stepping action is accomplished by switching the power to the motor windings so that the motor phases are energized in a specific sequence. Stepper motors are capable of very precise positioning without the use of complicated and expensive feedback devices. MDC uses SLO-SYN® DC stepper motors on all motion and manipulation instruments fitted with stepper motors. These are brushless, permanent magnet motors that have full-step increments of 1.8°. They can also be made to operate in increments of 0.9° to 0.014° when half stepping or microstepping techniques are employed. SLO-SYN® motors have permanent magnet rotors and eight-pole stators. They do not have brushes, ratchets or detents to wear out and they use shielded, lubricated-for-life ball bearings to insure maximum reliability and long life. Tests indicate a typical minimum life of five years. These stepper motors operate on phase-switched DC power. The motor shaft advances in steps of 1.8° (200 steps per revolution) when a four step (full-step mode) input sequence is used and in steps of 0.9° (400 steps per revolution) when an eight-step (half-step mode) input sequence is used. 

Microstepping is a method of stepper motor control that allows the rotor to be positioned at places other than the 1.8° and 0.9° positions provided by the full-step and halfstep methods. Microstepping occurs between these two angular points in the rotation of the rotor. These stepper motors are suitable for 1/10 and 1/125 microstep increments. A benefit of microstepping is that it reduces the amplitude of the resonance which occurs when the motor is operated at its natural frequency or subharmonics of that frequency.

In-Vacuum Stepper Motors

In-vacuum stepper motors are ideally suited for the precision movement of delicate specimens such as silicon wafers in ultrahigh vacuum. The use of in-vacuum stepper motors results in considerable savings in mechanical complexity with resultant gains such as cost reduction, improved reliability and decreased backlash. In some cases the use of in-vacuum motors can mean the complete elimination of edge welded bellows. The particulate generation of these stepper motors is minimized by the total absence of metal to metal sliding surfaces. This and their low outgassing characteristics make these motors especially suitable for sensitive semiconductor handling applications. Other applications for which these motors have been employed include precision in-vacuum UHV manipulators, monochromator mechanisms for synchrotrons, ion beam lithography and sample transport in UHV.

Motor Controls

All motor controls are sold separately and are not included in the motorization option prices.

Alternating current (AC) motors do not require motor controls since they are designed to be wired directly into an alternating current wall circuit. 

DCM-SC-90 controllers are designed for use with 90 VDC motorized instruments. This controller provides bidirectional motor control in continuous and jog modes. Motor speed is adjustable from 0 to 10 rpm via voltage regulation. Feedback circuitry uses the motor’s “Back-EMF” to provide a flat torque-speed curve. Additional features include transient and surge protection, line voltage compensation, soft start, discrete silicon-controlled rectifiers and diodes for higher amperage output and better heat dissipation. Controller is wired for 115VAC input and is provided with a 2 conductor cable for direct connection to MDC 90V motorized components.

MDC now offers new 4.3” touchscreen controllers that are compatible with all standard stepper motor options for rotary,linear and XYZ stages. The controller package includes everything you need to drive an MDC motorized feedthrough. All cables and connections are pre-terminated to work together for a no fuss simple installation. Controllers are available in single axis or three axis versions. They can be programmed to deliver output commands directly to the motor or can be connected to a computer via RS485 with options for RS232, USB, Ethernet or DeviceNet™ connections. These controllers are the ideal solution for your precision motion applications.

To learn more about these options, email inquiries to or contact MDC Technical Sales team by phone at 800-443-8817.


Direct current stepper motors




 In-Vacuum Steeper Motors
For product listing, features and specifications click on links below
 Miniature High Vacuum
 High Torque High Vacuum
 Miniature Ultra High Vacuum
 High Torque Ultra High Vacuum


 Motor Controls
For product listing, features and specifications click on links below
 Touchscreen Stepper Motor Controllers
 DC Motor, 90V Output


MDC Stepper Motor Controller and Indexer are obsolete and no longer available.

MDC Stepper Motor Controller part number 692005 Model SMC-M and Stepper Indexer part number 692006 Model SMC-1 are obsolete and are no longer available. They are being replaced by new and improved stepper motor controller packages that include single and multi-axis functionality. MDC has also developed a new on-board "Smart Motor" option. "Smart Motor" technology features a stepper motor with integrated controller and indexer that is mounted directly to the stepper motor.

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