New Autoclavable brushless DC motor range and sterilisation cycles

Autoclavable DC motors together

There are many different benchmarks in the marketplace for the sterilisation capabilities of devices. maxon motor explain the cycle and testing process for Autoclavable brushless DC motors.

maxon motor develop brushless DC motors that can be sterilised for medical and dental applications. Recently released is the new ECX range of motors with sterilisation capability on 13,16,19 and 22mm diameter versions. The new range of motors complement the existing 4 pole sterilisable 30mm brushless 150W motor and offer high speed capability up to 120,000rpm. maxon motor test the brushless motors to either 1000 autoclave cycles or 2000 cycles depending on the product. For motors with hall sensors fitted the motor is typically cycled through 1000 autoclave cycles and without hall sensors 2000 cycles. Gearheads are available with additional shaft seals. With the additional seal they are tested to 2000 cycles and without, 1000 cycles. Another new product that offers a completely sterilisable positioning system for the first time is an encoder rated and tested for 1000 cycles.

The maxon motor internal autoclave testing is carried out with the autoclave with a vacuum phase. The motors are unpacked and mounted without any additional protection. Three vacuum cycles are made at the beginning to ensure the internals of the motor become damp. The sterilisation atmosphere is built up with steam which remains constant for 18 minutes at 134˚C, 100% humidity and 2.3 bar of pressure. The unit is then cooled to 70˚C and dried. Each individual autoclave cycles takes approximately 1 hour. After 100 cycles the motors are removed from the autoclave and visually checked and motor operation is checked. Following this the motor is then removed after 250 cycles and visually checked in addition to data acquisition of the running data, motor noise, vibration and electrical strength test at up to 500V DC. Typical batch test cycles are conducted with 10 pcs and the tests are repeated with design changes. Internal testing of the motors to 2000 cycles takes approximately six months.

Contact maxon motor Australia for assistance with Autoclavable brushless DC motor options Tel. +61 2 9457 7477.

A DC motor kit supplied in parts for robotic joint applications.

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Maxon’s brushless frameless DC motors are designed for applications with space and weight constraints.

DC motors don’t always fit seamlessly into applications. Particularly in robotic joints, the space and weight constraints can take off the shelf DC motors past their threshold. These motors must also offer high torque yet be lightweight to meet the needs of the application’s dynamic movements. For this growing market, maxon motor developed a brushless flat motor as a frameless kit. The rotor and stator are provided separately, without bearings and motor shaft and connected when these components are put together. This offering brings the best of both worlds: high torque density with the smallest dimension possible. With outer diameters of only 43 to 90 mm, the brushless frameless flat motors are particularly compact. Designed as external rotor motors, they offer plenty of space inside for cable glands. For easy control these are delivered with Hall sensors.

The benefit of the brushless frameless motor kits are low cogging torque, high overload capacity, high torques through the multi-pole external rotor, space for cable glands, supplied equipped with Hall sensors and thermal sensors, and speaking from our own experience; higher levels of integration into robotic joint applications.

For more information on robotic applications or maxons brushless frameless motor kit, please contact maxon motor Australia tel. +61 2 9457 7477.

Brushless DC motor – pushing it to the limit

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When prototyping for applications with extreme requirements for brushless DC motors, fast condition monitoring is critical.

Motor applications with limited space available and comparatively large power requirements can push a motor very close to burning out. In theory, it is possible to use temperature calculations for the motor winding with the help of thermal resistance rating from the motor data sheets, ambient temperatures, heat sinking details and housing characteristics. This is always considered first and then tolerances and safety margins are considered. Following this thermal modelling software and imaging can be evaluated. However some applications push a motor so close to the edge, that only real product prototype testing can be relied upon. Simply installing motors and testing how hard you can push them can also be a costly exercise and does not give enough reliable data. Actual winding temperature sensing on the motor is a solution maxon motor offer for these extreme cases. By inserting sensors through ports in the magnetic return stack and in direct contact with the winding, maxon motor can give customers a device that monitors winding temperatures without the thermal time constant delays experienced when measuring winding resistance and using housing thermal time constants.

For more information please contact maxon motor Australia tel. +61 2 9457 7477.