Februar 28, 2024

Basic knowledge of servo drives

As an important part of industrial control equipment, servo drives are the core of achieving high-precision and high-efficiency motion control.

This article aims to help everyone understand the basic principles and working methods of servo drives, master the causes of common faults and repair methods, thereby effectively improving the efficiency and quality of maintenance services.

A servo driver generally consists of a power supply, main circuit, drive circuit, detection and protection circuit, control circuit, speed feedback circuit, etc. It is a closed-loop control system.

Ⅰ. Common faults of servo drives include

No power supply, input and output phase loss, overcurrent, overload, overvoltage, overheating, undervoltage, short circuit, grounding, etc.

1. There may be several reasons for these failures.

2. No power supply: This may be caused by a faulty power line, tripped circuit breaker, faulty power module, etc.

3. Input and output phase loss: It may be caused by power line problems, poor contact, relay failure, etc.

4. Overcurrent: It may be caused by unstable power supply, overload, motor failure, control system failure, driver internal component failure, etc.

5. Overload: It may be caused by unreasonable system design, sudden load changes, unreasonable overload protection parameter settings, etc.

6. Overvoltage: It may be caused by power fluctuations, grid problems, internal faults of the driver, etc.

7. Overheating: It may be caused by excessive ambient temperature caused by dust and oil in the environment, poor heat dissipation, fan failure, internal component failure of the drive, etc.

8. Undervoltage: It may be caused by power supply problems, line damage, power grid fluctuations, etc.

9. Short circuit: It may be caused by line short circuit, component aging, internal component failure, etc.

10. Grounding problem: It may be caused by grounding line problems, poor connections, poor equipment installation environment, etc.

Ⅱ. The causes of equipment damage can be attributed to several factors

1. Load Impact

Load impact refers to the sudden changes in load that a machine or piece of equipment experiences during operation. This can be caused by rapid starting or stopping of motors, sudden application or removal of load, or any abrupt shift that places mechanical stress on the system. The effects can lead to increased wear and tear, potential mechanical failure, or even immediate damage to the equipment, especially if it is not designed to handle such dynamic loads.

2. Unstable power supply

An unstable power supply can cause voltage and current fluctuations that are detrimental to the proper functioning of electrical equipment. Voltage spikes or drops can cause malfunction, overheating, or damage to sensitive electronic components. Constant power instability can shorten the life of machinery and lead to unpredictable failures.

3. Dust and oil in the environment

Environmental contaminants such as dust and oil can have a significant impact on equipment performance and longevity. Dust can accumulate on electrical contacts, causing resistance and potential arcing, while oil can cause components to degrade or fail due to chemical reactions. Both can interfere with heat dissipation, leading to overheating and reduced efficiency or malfunction.

4. Component aging

Over time, all components within a machine will naturally age and degrade. This aging process can include wear of mechanical parts, degradation of electrical insulation, or depletion of chemicals in batteries or capacitors. As components age, their performance can deteriorate, leading to reduced efficiency and increased risk of failure, requiring regular maintenance and replacement to keep equipment running smoothly.

According to rough statistics based on experience, there are 30% power supply failures, 30% drive circuit failures, 30% detection circuit failures, and 10% motherboard failures.