Why Linear Actuators Draw More Current in Cold Temperatures

Running Actuators in cold temperatures, and what you can do to improve their performace in cold weather. 

Linear actuators are vital components in many applications, but their performance can be significantly affected by temperature fluctuations, especially in colder environments. One of the most noticeable impacts of cold weather is an increase in current draw. In this blog post, we’ll explore why this happens, how current draw changes across different temperatures, and practical solutions to mitigate these issues.

The Science Behind Increased Current Draw in Cold Temperatures

Linear actuators experience higher resistance and inefficiencies in cold environments due to several physical and mechanical factors:

1. Increased Viscosity of Lubricants

   • Standard lubricants inside actuators, such as grease or oil, thicken in cold temperatures, increasing their viscosity. This creates greater resistance in moving parts like gears, lead screws, and bearings, requiring the motor to exert more effort to move the load, which in turn increases the current draw.

2. Material Contraction

   • Cold temperatures cause metal components to contract, which can tighten clearances between moving parts. This added friction further increases the load on the actuator’s motor, demanding higher power.

3. Reduced Motor Efficiency

   • Electric motors are less efficient in cold environments. The electrical resistance of the motor windings changes with temperature, and magnets may exhibit reduced performance, leading to decreased efficiency and increased current draw.

4. Startup Current Spikes

   • The first inch of movement is often the most challenging for an actuator, especially when it’s cold. The motor requires additional torque to overcome initial static friction, and in low temperatures, this effect is amplified.

Current Draw vs. Temperature Chart

Below is a general illustration of how the current draw of a linear actuator might change across a range of temperatures, from extreme cold (-40°F) to warmer conditions (65°C / 149°F). This is a generalized trend based on typical actuator behavior:

(Note: Actual values will vary depending on actuator model and application.)

Mitigating Cold-Weather Challenges

While you can’t change the internal mechanics of an actuator after purchasing it, there are effective ways to help it operate more efficiently in cold temperatures.

1. Insulation for the Actuator

Insulating the actuator is one of the easiest and most cost-effective ways to protect it from extreme cold. Proper insulation helps maintain a more stable internal temperature, reducing heat loss.

• Best Insulation Materials:

  • Closed-cell foam: Lightweight and moisture-resistant, it is ideal for creating a thermal barrier.

  • Aerogel insulation blankets: These provide superior thermal resistance in thin layers, though they are more expensive.

  • Neoprene wraps: Durable and flexible, these wraps offer both insulation and weather resistance.

• Insulation Effectiveness:

  • A well-insulated actuator can maintain a stable internal temperature for several hours, depending on ambient conditions and insulation thickness. Combining insulation with an external heat source significantly extends this time.

2. Heat Jackets

Heat jackets are pre-made thermal wraps with integrated heating elements. These are specifically designed for cold-weather applications and are easy to install around the actuator.

• Advantages:

  • Provide consistent, controllable heat.

  • Easy to remove when not needed.

• Power Requirements:

  • Heat jackets typically operate on low power (12V DC or 120V AC) and draw minimal current.

3. Heating Coils

Heating coils or pads can be installed around the actuator or its housing to keep the unit warm during operation.

• Installation Tips:

  • Ensure even placement to avoid hot spots.

  • Use a thermostat or temperature controller to maintain a steady temperature and prevent overheating.

• Power Efficiency:

  • Heating coils are energy-efficient and can maintain the actuator’s temperature with minimal power consumption.

4. Pre-Warming Cycles

Before operating the actuator under load in cold conditions, perform a no-load warm-up cycle. This allows internal components to move and generate heat, reducing startup friction and current spikes.

5. Protective Housings

Place the actuator inside a weatherproof, insulated housing. This protects it from direct exposure to cold wind, snow, or rain, and helps retain heat from other warming methods.

• Recommended Housing Materials:

  • ABS plastic or fiberglass for lightweight, durable protection.

  • Aluminum with an insulated lining for extreme conditions.

Practical Applications of These Solutions

• Automotive: Insulate actuators used in tailgates or snowplows to ensure reliable performance during winter.

• Industrial Equipment: Use heat jackets or heating coils for actuators in outdoor machinery to maintain efficiency.

• Residential Use: Protect actuators in garage doors or gates with insulated housings or pre-warming cycles.

Conclusion

Cold temperatures pose significant challenges to linear actuators, increasing their current draw and reducing efficiency. By understanding the causes of these issues and implementing practical solutions like insulation, heat jackets, or pre-warming cycles, you can ensure reliable actuator performance even in extreme cold. Taking these proactive steps will help extend the life of your equipment and prevent unnecessary downtime.

For more tips or recommendations tailored to your specific actuator model, feel free to reach out to our team.