Why Motor Bearings Noise Become More Prone in Winter?

Introduction

Have you ever wondered why motor bearings’ noise becomes more pronounced in winter, especially in certain parts of the world?
If you’re scratching your head over this, you’re not alone. Engineers in northern China often face this issue, where motors produced in winter show higher rates of bearing noise compared to those made in summer.
But why does this happen? And why is it more common in places like Hebei, Henan, and Shandong, while the northeast and southern regions seem less affected? Let’s dive into the fascinating world of motor bearings and lubrication to find out.
An electric motor, electric motor noise is always a big question
electric-motor

The Temperature Trap: How Cold Weather Affects Lubrication

At the heart of this winter noise mystery is lubrication—specifically, the grease used in motor bearings. Grease is like the motor’s secret sauce, keeping everything running smoothly. But here’s the catch: grease changes with temperature.
  • In summer, when it’s warm (around 20-30°C), grease is like runny honey—smooth and easy to spread.
  • In winter, when temperatures drop (sometimes below 0°C in northern China), grease thickens up, more like cold butter—stiff and harder to move.
This change in thickness, or viscosity, is key. When motors are designed, the grease is chosen based on the expected operating temperature, not the cold start-up temperature. So, in winter, when you start a motor, the grease is thicker than it should be. This leads to:
  • Increased churning: The motor has to work harder to move the thick grease.
  • Higher noise levels: The bearings might not roll smoothly, causing a racket.
Think about it: Ever tried stirring a pot of cold, thick soup? It’s noisy and takes effort. That’s what’s happening inside your motor!

Regional Riddles: Why Some Areas Are Hit Harder

You might be wondering, “If it’s cold in the Northeast too, why don’t they have the same problem?” Great question! The answer lies in how factories manage their environments.
  • Northeast China: Winters are harsh, but factories often have central heating. This keeps production areas warm, so the grease doesn’t get too cold.
  • North-central China (Hebei, Henan, Shandong): Factories might not heat as effectively, leaving production and storage areas chilly. Cold grease = noisy motors.
So, it’s not just the outside temperature but the indoor environment that matters. A warm factory can dodge the winter noise bullet!

Case Studies: When Lubrication Goes Wrong in Winter

Let’s look at two real-life scenarios that highlight how winter affects motor lubrication.

Scenario 1: Adding Grease in Winter

Imagine it’s a freezing winter day, and you’re maintaining a motor by adding fresh grease. But suddenly, the motor gets louder. What gives?
  • The problem: The new grease is cold and thick, while the grease already in the motor is warm and thin. Mixing them creates a messy, inconsistent blend.
  • The result: Motor bearings struggle, leading to increased noise. In extreme cases, the thick grease can even scratch the bearing surfaces.
  • The Case: There was a case where a problem arose due to temperature differences during lubrication.
Pro tip: Warm up the new grease before adding it. Let it sit indoors until it’s closer to the motor’s temperature. This “temperature matching” can save you a lot of trouble.

Scenario 2: Starting a Motor in Winter

You flip the switch on a cold winter morning, and the motor roars to life—literally. It’s louder than usual. Why?
  • The issue: After sitting idle, the grease has thickened due to the cold. When you start the motor, the bearings have to push through this thick grease, causing noise.
  • The fix: Preheat the bearing area slightly before starting the motor. This helps the grease loosen up, reducing noise and potential damage.
A motor mounted in an extremely cold outdoor environment, motor bearings noise becomes common
motor-in-cold-environment

Designing for the Climate: Why Location Matters

Motor designers need to think about where the motor will be used. The operating environment can vary wildly:
  • Cold climates (like Russia): Motors need grease that stays effective at low temperatures.
  • Hot climates (like India): Motors require grease that doesn’t thin out too much in the heat.
For example, a motor designed in southern China (warm) but used in Russia (cold) might not perform well if the grease isn’t suited for freezing conditions. Similarly, standard grease in China might be too thin for India’s scorching heat.
Key takeaway: Always match the grease to the expected operating temperature, not just the production environment.

The Frosty Finale: Condensation and Frost in Bearings

Winter brings another sneaky problem: condensation and frost. When motors heat up and cool down, the bearing housing can “breathe,” sucking in moist air. This can lead to:
  • Water droplets forming inside the bearing.
  • Frost if temperatures drop below freezing.
Moisture is bad news for bearings—it can cause rust and ruin lubrication. To prevent this:
  • Seal it up: Make sure the bearing housing is well-sealed.
  • Consider the duty cycle: If the motor frequently starts and stops, temperature swings are more likely, increasing the risk of condensation.

Wrapping It Up: Winter Wisdom for Motor Maintenance

So, why do motors get noisier in winter? It all boils down to temperature and lubrication. Cold weather thickens grease, making bearings work harder and noisier, especially during start-up or after adding new grease. But with a few smart moves—like warming up grease and preheating bearings—you can keep your motors humming quietly all year round.
Quick tips to remember:
  • Warm up new grease before adding it in winter.
  • Preheat bearings before starting motors in cold conditions.
  • Design with the climate in mind—choose grease that fits the operating environment.
Have you noticed your motors bearing noise in winter? If you need more solution for motor bearing, contact us!