LG Motion Systems have introduced a range of vacuum rated, brushless servo and stepper motors from Empire Magnetics, the USA based manufacturer of specialty motors. With three grades to choose from, covering laboratory, standard and commercial specifications, customers are able to exactly match application, price and performance requirements for vacuum prepared motors with peak torque ratings of up to 100 Nm. NEMA frame stepper motors with drive shafts or leadscrew/nut actuator drives and framed or frameless brushless servomotors are available.
The VX Laboratory Grade range has a vacuum rating of 10-7 Torr with internal temperature rating of 180o C and 155o for the case. The bearing lubricant vapour pressure is below 10-9 Torr at 100o C. This motor is cleaned and baked, and undergoes a proprietary extraction process to remove contaminants and must be handled under clean room conditions with nylon gloves.
This premium product offering is typically used when even very small amounts of contamination are of concern to the customer. Applications include space based optical systems, semiconductor manufacturing chambers and electron beam equipment.
VS Standard Grade vacuum motors are also rated to 10-7 Torr but with a temperature rating of 155o C internal and 130o for the case. The bearing lubricant vapour pressure is below 10-8 Torr at 100o C. During manufacture, this motor is subjected to an industrial cleaning process and is vacuum baked to encourage outgassing of residual contaminants and sealed in a nylon bag.
This “standard" product offering is typically used when very clean is good enough. Often the VS grade is selected for vacuum chamber applications where the chamber will be opened frequently; the contamination from the outside air will normally exceed that of the VS grade equipment, so it is deemed suitable for the application. Application areas include sputtering and diffusion equipment and standard grade vacuum motors have recently been tested to exceed Class 10 clean room requirements.
The VC Commercial Grade range has a vacuum rating of 10-6 Torr. These motors are temperature rated at 130o C internal, and 105o for the case. The bearing lubricant vapour pressure is below 10-6 Torr at 100o C. This motor will give off a small quantity of vaporisation products and no special handling is required. This range is aimed at vacuum forming, casting and welding applications.
Vacuum compatible brushless resolvers are also available and a wide range of accessories includes gearboxes, feedback devices, brakes and temperature sensors.