Frequently Asked Questions


  • Can your motors be driven at something other than their nominal voltage?

    Yes. DC motors (brush and brushless) have a very linear behavior: the speed of a motor is directly proportional to the voltage applied. For brush DC motors it is preferable not to run faster than the maximum recommended speed given in our datasheets. Therefore the voltage should be preferably close to the nominal voltage or lower. Since the motor life is affected by the speed of operation, operating the motor at lower voltages means less brush/commutator wear for all brush type motors. However if your application requires higher speed performance, overdriving the motor is possible. This will increase the speed at the expense of expected life. For DC brushless motors there is no brush commutation and the main contributor affecting lifetime is the ball bearings. However, our magnetic design optimizes the iron losses in the range of the nominal speed. Iron losses are proportional to the square of the speed. Overdriving the motor at a speed 1.5x higher than the nominal speed will increase the iron losses by a factor of 2.25x, which will drastically reduce the efficiency and overall motor performance. Stepper motors are often used with much higher voltage in chopper mode to achieve better dynamic performance.

  • Are your motors/gearmotors capable of withstanding industrial application environments?

    Our products are used in a variety of industrial environments, such as factory automation, automotive hand tools, assembly plants, machining applications, semiconductor plants, HVAC, and robotics. We can also provide autoclavable motors/gearmotors for medical and dental applications. If your application requires a motor/gearmotor to be used in an extreme environment, please consult with our application engineers for the best suitable product for the application.

  • Can your motors be used as generators?

    Yes, DC brush type motors can be used as generators. The disadvantage is they offer very low voltages. For assistance please contact our application engineers to discuss your application.

  • Is it possible to have a custom shaft made on the motor, such as a flat or D-cut shaft?

    Yes. You can specify where you want a flat on a shaft. You can also specify if you want a hole through the shaft, a pinion or pulley attached to the shaft, or a special sized shaft. Minimum order requirements may apply.

  • There are shafts on both ends of the motor. Is it available with a single shaft?

    In most cases, yes. You can select almost all of our motors (brush, brushless, and stepper) with either a single output shaft or a double shaft. Call one of our Sales Associates if you want specific information on pricing and product availability.

  • Do you have speed-torque curves available for your motors?

    Many speed-torque curves are available on the motor specification pages in our catalog. You can also submit an inquiry letting us know for which product you require a curve and our application engineering team will let you know if there is a speed/torque curve available.

  • What factors affect motor noise

    Our motors are designed for quiet operation. This is achieved through our proprietary motor design techniques and material selection. There are many factors to consider, such as how the motor is mounted in the application and the load and speed at which the motor will operate. Another consideration is the type of bearings selected for the motor and/or gearmotor. Before making a final selection, the motor/gearmotor being considered should be thoroughly tested in the design for audible noise levels if this is a concern for the application.

  • Can Portescap add cables and connectors to the motor?

    Yes, we have the capabilities to add cables and connectors to any of our motor products. For a quote on adding a special requirement, please call our application engineers for assistance with your design.

  • Can any of your motors and gearheads be combined?

    We have the capability to assemble all of our motors with a gearhead to provide the performance you require. Our motor specification pages shows which gearheads are designed to be assembled with each motor. Our application engineers are available to discuss your questions concerning compatibility of a product and make recommendations on the best product for the design criteria.

  • How long do your motors and gearheads last?

    Every application differs in life of a product: operating environment, input power, and duty cycle all affect the life. Even how the motor or gearmotor is connected to the load affects the products total life performance. Other parameters to consider in estimating overall life are back-driving the gearmotor or running the motor or gearmotor into a hard stop. If your application requires the motor or gearmotor to have high axial or radial loads, ball bearings would increase expected life. If your design requires long life as one of the parameters, you may want to consider using one of our brushless motors. Brushless motors are generally only limited in life by the ball bearings which support the shaft. Our application engineers are available to discuss your questions concerning life of a product and make recommendations on the best product for the design criteria.

  • What's the difference between a "servo" motor and a regular motor?

    A servomotor uses an automatic device such as an encoder for error-sensing feedback to correct the performance (motion, velocity, position and/or torque). It is considered a closed loop feedback system where the repeatability and accuracy are an important application requirement. Open loop or "regular" motors are used when performance feedback data is not critical for the application. An encoder can be added to most motors to close the loop and provide performance feedback.

  • Are you brushless motors autoclavable?

    We offer a full line of brushless DC slotted motors that are available with autoclavability. These motors are uniquely designed to meet the requirements of sterile and other demanding environments. Our autoclavable motors have been life tested to withstand in excess of 1,000 autoclave cycles. Medical applications that require autoclaving frequently utilize our brushless motors.

  • Can you run Portescap brush DC motors and gear-motors on batteries?

    Yes, the Portescap coil has been constructed so there is no moving iron in the rotor. We designate this type of motor construction as an Ironless coil. In this Ironless coil only the copper coil turns (around an immobile magnet system). This makes the rotor inertia extremely small and able to run at very low current levels. This type of design is most favorable for battery powered applications. In fact, our Athlonix motors have been uniquely designed to excel in performance for battery applications.


  • What types of encoder do you have?

    Optical, magnetic and magnetoresistive types.

  • Can I get feedback devices such as an encoder or other components put on our motor?

    Yes, each of our products are designed to accommodate a variety of complimentary devices as follows: spur or planetary gearboxes, optical or magnetic encoders, power-on and power-off brakes.

  • What is a magnetoresistive encoder?

    Portescap's high resolution MR encoders exploit the anisotropic magnetoresistance effect to provide analog signal that can be interpolated to generate lines. The number of lines per revolution can be set on our chip, up to 512.


  • Are all of your gearheads reversible?

    Yes, all planetary and spur gearheads are designed for bi-directional operation.

  • When should I use a planetary gearhead or spur gearhead?

    Spur gearheads are utilized when low current consumption, low noise, and high efficiency are a requirement. However they are limited when high torque must be transmitted. Planetary gearboxes typically exhibit higher current consumption, lower efficiency, and higher audible noise levels. But they are the best solution when high torques are required in an application with size limitations.