Troubleshooting: How to fix drive errors

1. Introduction

No matter how high-quality or precise a product is manufactured, operational issues can still arise. Depending on the issue, it might be resolved with simple lubrication, or in more severe cases, continued operation could lead to product failure. This section provides information on potential error symptoms, the causes of these symptoms, and possible corrective actions.

2. Squeaking noises

A squeaking noise usually occurs when two surfaces slide against each other without a lubricating film. Worn parts also often produce squeaking noises before they fail. The source of the issue can arise at any friction point:

2.1 Causes

1. Insufficient lubrication

If moving parts have not been lubricated for a while or if the spindle does not fully engage with the nut, the contact between the sliding surfaces can produce an unpleasant squeaking noise.

2. System tension

If the spindle-nut system is installed with tension or lacks sufficient degrees of freedom, heating can cause the system to become tense, leading to excessive pressure on the guide bushings (usually on the housing).

3. Side forces

The cause of the squeaking in this case is similar to tension. Increased pressure in the guide bushing can lead to excessive contact.

2.2 Actions

1. Ensure that the spindle or chain is adequately lubricated. For cylinder systems, the spindle can be lubricated through the grease nipple when the piston rod is extended. Caution: While too much grease won't cause damage, it may contaminate the surrounding area or require more force from the lifting element.

2. Never use a fixed-fixed bearing combination. The lifting system must be able to expand.

3. Tension is often noticeable when a mounting point is released. If the system "bounces back" to its untensioned state, the lifting element was not installed according to tolerance specifications.

4. Side forces can arise from factors such as wind, excessive tolerances in steel construction, or accelerations from conveyor systems. Ensure that side forces are minimized as much as possible. For inaccurate steel construction, machine levels or laser systems can assist in alignment.

3. Motor doesn't start or draws too much power

When the motor does not start or draws excessive power, it can be due to mechanical or electrical causes:

1. The lifting system is subjected to a higher load than originally assumed
2. The lifting system was incorrectly dimensioned
3. The motor is not supplied with the correct voltage
4. The brake does not open

3.1 Causes

1. If the lifting system is under a greater load than initially specified, the motor may not start because it cannot overcome the starting torque. This also applies to an incorrect dimensioning of the lifting system.

2. If the motor is supplied with a voltage that differs from its rated value, it may not deliver the nominal power. The motor’s nameplate provides this information.

3. If the motor has an additional brake, it's normally closed when not powered. It remains closed if the incorrect voltage is applied.

3.2 Actions

1. Check the applied load on the lifting system. Has there been a change from your original design? What revision was used for the most recent calculation? You have two options: either upgrade the motor to increase its power, or equip the existing motor with a reduction gearbox (this will make the lifting system operate more slowly but with less power). Note: The lifting element must also be able to handle the increased load.

2. Check the power supply and fuses to ensure they are properly supplying the motor and brake. If the nameplate does not provide sufficient information, request the technical data or a wiring diagram from us.

4. Grease and oil leakage

Greases and oils play a crucial role in extending the lifespan of sliding components. They are responsible for heat dissipation within the gearbox, protecting surfaces against wear and rust, and they have the ability to "creep" to hard-to-reach areas.

4.1 Causes

1. Grease Bleeding: Greases can experience "bleeding," where the liquid and solid components of the grease separate. This usually occurs after long periods of inactivity. This often happens when gearboxes are stored as spares for a long time before being put into use.

2. Overfilled Grease Box: Spindle drive systems are delivered with a grease filling. If the gearbox is overfilled, excess grease may be pushed out of the casing during operation.

3. Damaged Seals: If seals on the lifting element are damaged during transport or installation, grease can leak out freely. This effect is amplified during operation as the grease/oil expands.

4. Standard Screw Jacks: Screw Jacks installed overhead tend to have a higher tendency for grease leakage. The desired effect of the spindle carrying the grease out of the gearbox is enhanced by gravity, which can lead to excessive "grease transport."

4.2 Actions

1. Regularly mixing the grease helps prevent bleeding. Recommissioning an existing element can also be resolved by mixing. Alternatively, perform a grease change before using the gearbox.

2. Damaged seals can often be replaced with minimal effort. If the drive is still under warranty, send it to us, and we will handle the correction.

3. To eliminate the effect of grease transport, a two-chamber lubrication system can be chosen (only possible BEFORE ordering the drive). This seals the gearbox completely. Note: The spindle must then be manually lubricated.

5. Overheating of the gearbox

A lifting drive should not exceed a surface temperature of 80°C (176°F). While this can feel very hot, it does not necessarily indicate overheating. All screw jacks are equipped with a temperature sensor that changes color irreversibly. This color change reliably indicates overheating.

5.1 Causes

1. If a lifting element is operated beyond the permitted duty cycle per hour, it doesn't have sufficient cooling time. Since heat does not dissipate immediately but tends to accumulate, continuous operation leads to heat buildup.

2. An overload results in more power being converted into heat within the system. Overloading can occur due to excessive load or increased friction (see also the topic of tension).

3. An unlubricated lifting system will generate more heat due to poor sliding performance. In this case, overheating is due to insufficient lubrication.

5.2 Actions

1. Incorporate more downtime into your process. If a specific cycle rate must be achieved, only drives with higher efficiency will help. For example, screw jacks originally equipped with trapezoidal screws can be upgraded to ball screws, typically improving efficiency by over 25%.

2. Make sure that the load is within limits and that the lifting elements are installed according to the allowable tolerances.

3. Insufficient lubrication often results in squeaking noises and higher motor current. If this occurs, a simple re-lubrication may resolve the issue.