ISG Pipeline Centrifugal Pump Bearing Overheating: Is It Always a Lubrication Problem?

ISG Pipeline Centrifugal Pump Bearing Overheating: Is It Always a Lubrication Problem?

In HVAC circulation systems, water supply networks, and industrial fluid transport, ISG pipeline centrifugal pumps are widely used for their compact structure and stable operation.

However, one common issue frequently observed on-site is:

👉 Bearing overheating during operation

Many operators immediately assume:

👉 “It must be a lubrication issue”

But real-world engineering experience shows that:

👉 Lubrication is only one of several possible causes

👉 Reference analysis:

https://www.scpv.cn/news/880.html

1. First principle: why do bearings overheat?

The root cause of bearing overheating is:

👉 Increased friction and abnormal load

Lubrication affects friction—but it is not the only factor.

2. Lubrication issues (yes, but not the whole story)

Typical lubrication-related causes include:

Insufficient or excessive grease

Degraded or contaminated lubricant

Incorrect lubricant type

These conditions can:

👉 Increase friction → raise temperature

Also, improper oil quantity (too much or too little) can both lead to overheating.

But in many cases, adding lubricant does not solve the problem—because:

👉 The root cause lies elsewhere

3. Cause #1: Misalignment (very common)

If there is:

Misalignment between motor and pump shaft

Improper coupling installation

This leads to:

👉 Additional radial load on bearings

Result:

Uneven stress distribution

Rapid temperature rise

Misalignment is one of the most overlooked causes in practice.

4. Cause #2: Abnormal axial force

When the pump operates away from its design point:

Low-flow operation

Improper valve adjustment

It causes:

👉 Changes in hydraulic forces

Result:

👉 Increased axial load on bearings → overheating

5. Cause #3: Bearing or rotor defects

Examples include:

Bearing wear or damage

Rotor imbalance

Shaft bending

These issues lead to:

👉 Vibration + increased internal friction

Which directly causes:

👉 Temperature rise

6. Cause #4: Mechanical and installation factors

Such as:

Excessive bearing preload

Tight internal clearance

Improper installation

These conditions increase:

👉 Mechanical resistance

Leading to:

👉 Heat generation

7. Cause #5: Operating conditions

Common real-world issues:

Long-term low-flow operation

Frequent start-stop cycles

Motor overload

These conditions cause:

👉 Continuous abnormal stress on the pump

And ultimately:

👉 Bearing overheating

For example, low-flow operation can cause poor internal circulation and heat buildup.

8. Cause #6: Poor cooling conditions

Often overlooked factors:

High ambient temperature

Poor ventilation

These lead to:

👉 Heat not being dissipated effectively

Which amplifies the overheating problem.

9. Key insight: overheating is a system-level signal

Many operators treat bearing overheating as:

👉 A single-point failure

But in reality:

👉 It is often the result of multiple interacting factors

For example:

Slight misalignment + marginal lubrication + off-design operation

Combined, they lead to:

👉 Noticeable overheating

10. Practical troubleshooting logic

Quick diagnosis on-site:

Overheating only → check lubrication first

Overheating + vibration → check alignment/rotor

Overheating + noise → check bearing condition

Overheating + high current → check operating conditions

11. Engineering recommendations

To prevent bearing overheating:

Ensure proper shaft alignment during installation

Use correct lubrication type and quantity

Operate within the design performance range

Monitor vibration and temperature regularly

Maintain good ventilation and cooling conditions

Experienced manufacturers like Shanghai Shangcheng Pump & Valve typically address these factors during system design and selection to reduce long-term risks.

Conclusion

Bearing overheating in ISG pipeline centrifugal pumps is not always a lubrication issue. More often, it is:

👉 A combined result of alignment, load, vibration, and operating conditions

If you only focus on lubrication:

👉 The problem is likely to recur

Reliable operation depends on:

👉 System-level analysis, not single-component fixes