The design standards for radiation-resistant motors are not simply a matter of “reinforcement,” but rather a comprehensive engineering system based on total cumulative absorbed dose (Gy).
Specific Industry Applications
Nuclear Industry
Radiation Hardened Stepper Motors: These typically use open-loop control. They control the rotation angle via input electrical pulse signals; each pulse causes the motor to rotate by a fixed step angle. Positioning and speed control are achieved by regulating the number and frequency of pulses, with accuracy depending on the motor itself rather than external feedback. This control method offers relatively straightforward resistance to radiation interference.
Radiation Hardened Servo Motors: These belong to closed-loop control systems. They typically incorporate built-in feedback devices such as encoders or rotary transformers, which can monitor the motor’s speed, position, and other information in real time and feed this data back to the driver, thereby enabling high-precision, high-dynamic-response control. In radiation environments, the radiation resistance requirements for the entire control system—including feedback devices and drive circuits—are even higher.
Wheatstone Classifies Radiation Doses As Follows:
| Classification of Cumulative Radiation Doses | R1:Radiation Hardened: 103 Gy | R1:Radiation Hardened: 105 Gy | R1:Radiation Hardened: 106 Gy |
Cumulative radiation doses can reach up to 10^7 Gy, as well as neutron radiation
High Reliability and Stability: The motor can operate stably for extended periods under various combinations of extreme conditions, including high temperatures (up to +300°C), high vacuum (as low as 10⁻⁷ Pa), and cryogenic temperatures (as low as -196°C). This high level of stability significantly reduces the risk of failure during mission-critical operations.
Special Materials and Processes: To achieve radiation resistance and operation across a wide temperature range, the motor undergoes specialized material and process treatments. For example, it utilizes special radiation-resistant permanent magnets, specialized insulating coatings and adhesives, and employs lubrication solutions with low outgassing rates or solid lubrication technology to prevent material volatilization and environmental contamination in a vacuum.
This is the most critical advantage. The motor itself can withstand prolonged exposure to high-energy radiation (such as gamma rays and neutron flux), with a total dose of up to 10⁶ Gy or more, ensuring that it will not fail due to material degradation even in the core area of nuclear radiation.
Wide Temperature Range and Vacuum Compatibility
It can withstand extreme temperature fluctuations—ranging from high temperatures to cryogenic temperatures —and operate normally under high vacuum conditions . The material will not crack due to temperature differences, nor will the lubricant evaporate under vacuum conditions and contaminate other precision equipment.
Even under harsh operating conditions with minimal maintenance, these motors maintain an extremely low failure rate, with a design life typically spanning tens of thousands of hours. This high reliability significantly reduces the safety risks associated with motor failures in nuclear facilities or spacecraft.
Precise Control and Smooth Operation
As an actuator, it can respond precisely to control commands (particularly in the case of servo motors), providing high-precision position and speed control, and operating smoothly. This is crucial for precision operations such as manipulating robotic arms and adjusting nuclear reactor control rods in radiation environments.
| Base Size | Power Range | Speed Range | Voltage Range |
|---|---|---|---|
| 60mm | 0.2~0.6KW | 3000~4000rpm, Customized | 220V,380V |
| 80mm | 0.4~1KW | 3000~4000rpm,Customized | 220V,380V |
| 110mm | 0.6~1.8KW | 3000~4000rpm,Customized | 220V,380V |
| 130mm | 1.2~4.5KW | 3000~4000rpm,Customized | 220V, 380V |
| 180mm | 4.5~15KW | 3000~4000rpm,Customized | 220V, 380V |
| 260mm | Customized | Customized | 220V,380V |
| Name | Size | Category | Thumbnail | Download |
|---|---|---|---|---|
| Explosion Proof Servo Motor Technical Data.pdf | 89KB | Catalogue | | Download |

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The core engineering metric for measuring a motor’s radiation resistance is the cumulative absorbed dose, measured in gray (Gy), rather than the “number of irradiation cycles” or “years of service.” Radiation damage to the motor’s internal insulation materials and lubricating grease is an irreversible, cumulative process. The key premise behind the question customers often ask—“How many times can it withstand irradiation?”—is a clear understanding of the absorbed dose per irradiation cycle.
2.What is the typical magnitude of the “radiation resistance” of radiation-resistant motors?
Conventional motors may fail at doses as low as a few hundred gray (Gy), whereas truly radiation-resistant motors must meet different radiation resistance levels depending on the application:
Conventional nuclear industry applications: Typically require resistance to 10⁶ Gy (1 MGy) or higher.
High-demand scenarios (such as fusion devices): Technology exists to achieve radiation resistance of 10⁷ Gy (10 MGy) or even higher.
Limitations of drive circuits: It is important to note that while the motor itself is radiation-resistant, the radiation resistance of traditional drive circuits is often less than 10⊃3; Gy; therefore, hardened solutions such as FPGAs or gallium nitride (GaN) devices must be selected.
3.In a radiation environment, what is the component of an electric motor most prone to damage?
The most vulnerable parts of an electric motor are usually not the metal components, but rather the numerous organic material parts. These primarily include:
Insulation system: When exposed to radiation, the insulation varnish on enameled wire and insulation paper undergo molecular chain breakage, causing a sharp drop in insulation resistance.
Lubrication system: Ordinary grease can carbonize, form coke deposits, or volatilize in a radiation field, causing bearings to seize due to dry friction.
Seals and cables: Sealing rings and the insulation layers of lead wires are prone to hardening and cracking under radiation.