Custom Motors and Options
Frequently Asked Questions
To receive information on any of these questions, click the question
|Do you make motors that can tolerate more
than one harsh environment?
We can custom engineer motors to survive combinations of environments.
Requests for this particular combination of environments are difficult to respond to. One can build a motor or other piece of equipment that has suitable materials at the outset but once it is subjected to radiation the materials begin to change. The outgassing properties of the secondary materials as the result of radiation breakdown are unknown.
A motor can be made which will not corrode in typical wet environments, but if the water gets into the motor and then freezes, nothing can be done to make the motor operate when it is full of ice.
At very cold temperatures, the plastic used to insulate the wires or cable will crack and break if flexed. If the motor cable must move when cold, this issue needs to be considered.
While it is possible to make motors with windings to withstand high temperatures (180° C typical), many of the hazards encountered which would require purged and pressurized equipment have safe operating temperature requirements well below the temperature levels allowed by the HT motor. The user should consider the safety issues prior to requesting this particular combination of environments.
To prevent the build up of ice from moisture collection on the cold metal surfaces, the cryogenic motors are normally operated in a vacuum. Empire Magnetics, Inc. has designed the motors for this environment.
Yes, on a best-effort basis. To understand the efforts involved in this request one has to understand the materials that are used in the motors and the impact the material choices have on the customer. The materials of concern are the long chain molecules, or organic compounds.
Once the carefully selected vacuum compatible materials are subject to radiation the long chain molecules are broken down and the newly created materials have different physical properties, including different vapor pressures. As a result we cannot predict the outgassing rates of the motors after they are subjected to various levels of radiation.
The limiting factor for the waterproof radiation hardened motors is the shaft seal material. The best material we have been able to locate for this purpose is EPDM, which can be expected to break down between 106 and 108 rads t.a.d. (gamma radiation).
Yes, the submersible versions of the waterproof radiation hardened motors are oil-filled (with a reactor approved oil) and pressure compensated.
Yes, but for the following reasons this is not a standard product offering for Empire Magnetics: it is very expensive, there is little demand and our vendors require minimum orders of 1000 feet.
No, except for MIL-E-5400. The reason is that we do not have a sufficient number of contracts to justify the costs required to implement the programs. This problem is not unique to Empire Magnetics as the MIL-spec market is a shrinking one. Some time back the sales manager of a large motor company informed me that they had gotten into trouble on about 49 of the 52 contracts they had received, primarily because they were not getting the volume of business necessary to absorb the overhead. I am also aware that several suppliers of small military hardware have recently gone out of business.
The good news is that once customers become aware of the tremendous costs associated with the implementation of MIL-specs they are usually able to accept a functional equivalent. We have provided motors for the Wake Shield Satellite, the Japanese Space Agency, the European Space Agency, and the Smithsonian Observatory, for example, and a good deal of our success is due to our lower prices a direct result of not trying to do things the government way.