Lab Notes Articles

Did You Know?

• That teflon breaks down very quickly when subjected to gamma radiation?
• Under massive doses, teflon can be made to vaporize so rapidly that a toxic gas cloud is created.
  That Teflon recovers well from low temperatures?
• Teflon-insulated wires used at 20°K can be cycled to and from room temperatures without significant damage.
  That Teflon works well in a vacuum, and that its vapor pressure is similar to many metals?
  That Teflon is subject to “cold flow” and is not a good choice for machined parts when accurate dimensions must be maintained?
  That Empire Magnetics has supplied its specialized motors for satellite applications?
• One of our motor gearbox assemblies is mission-critical. The motor rotates the platform to orient the satellite antenna arrays. We are also supplying other, much smaller motors to the European space agency.
  That the power of a motor cannot be increased by adding a gearbox?
• Power is the multiple of speed times torque. Since a gear ratio will multiply the torque, but divide the speed, the only effect on total power is the reduction caused by the inefficiency of the gearing.
  That dry ‘lubes’ react in different ways to airborne moisture?
• Graphite requires moisture to lubricate, for instance. Molybdenum disulfide, however, absorbs moisture and degrades quickly. This is one reason why graphite is a poor vacuum lube and MSO2 is often used instead.
• There are many processes for applying MSO2 (or similar dry lubes): spraying it into the bearings is the method used for larger bearings (where clumps of lube are not significant); binders are used to “paint” the dry lube onto the metal surface; impingement is used to “hammer” the dry lube to the surface; flame plasma is used to fuse the material to the metal.
• The latest approach for applying dry lube is ion implantation, or deposition. None of these methods is without flaws, but the ion implant technique does seem to be best for instrument grade bearings for high precision applications.
  That the life of a stepper or brushless motor is limited by the life of the bearings and the thermal life of the insulation materials?
• Most motors fail not due to the end of the motor’s life, but because they are misapplied or have been abused by the people using them.