STRATEGIC MOTOR SELECTION
MOTOR SELECTION WHEN MAINTENANCE ISN’ T AN OPTION.
From pacemakers and neural implants to deep‐space probes, opportunities for maintenance are rare and sometimes non‐existent in mission-critical devices. In such applications, a single motor failure can be catastrophic. Here, Dave Walsha, sales and marketing director at drive system supplier Electro Mechanical Systems( EMS), shares advice on how to select the right motor to balance longevity, reliability and resilience in maintenance‐free systems.
Devices installed in inaccessible or extreme environments must withstand conditions that would otherwise degrade standard components, such as miniature DC motor bearings that can seize due to dust or vibration, precision gearhead teeth that wear under high loads and encoder contacts that fail from moisture or contamination. Even brief operational interruptions can carry high costs, particularly in highly-regulated industries such as aerospace, where a single motor failure on a satellite can cost millions and be impossible to repair.
When servicing isn’ t possible, predictive maintenance offers little value. Even if sensors indicate potential issues, engineers cannot intervene in remote or hazardous environments. Therefore, some motors must be able to operate reliably throughout entire lifecycles without intervention.
What maintenance-free really means
The term“ maintenance-free” can be ambiguous. In most cases, it means that routine maintenance is minimised or even unnecessary over the intended
operational life. For instance, brushless DC motors can operate for tens of thousands of hours without lubrication, reducing maintenance needs when installed in inaccessible applications.
Mission-critical systems are often specified with mean time between failures( MTBF) measured in hundreds of thousands, or even millions of operating hours. Achieving such resilience requires more than selecting a high-quality motor. It means engineers must evaluate the interaction of mechanical design, materials, thermal performance and operational loads – a holistic approach where every component and design choice is scrutinised for long-term resilience.
Environmental stresses, such as temperature extremes, vibration, moisture or chemical exposure, can accelerate wear, degrade insulation and increase corrosion risk. Therefore, engineers must select materials and designs that mitigate these effects from the outset, which can involve using specialised coatings, high-performance alloys and robust sealing techniques to protect the motor from harsh conditions.
Comparing motor technologies
Different motors present different advantages and limitations that engineers must consider. While brushed DC motors are an efficient, cost-effective choice for less demanding environments, their mechanical contacts are a potential failure point over extended lifetimes. Brushless DC motors, by contrast, eliminate brushes and commutators, enabling long-
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