Explosion proof servo systems operate in flammable and explosive environments, and their fault diagnosis and troubleshooting need to balance safety and professionalism. The following provides a systematic solution by analyzing the two core faults of encoder alarm and overload protection.
Encoder alarm: signal interruption and abnormal accuracy
As the core component of position feedback, encoder faults often manifest as "encoder disconnection", "communication error" or decreased positioning accuracy displayed by the driver. Common reasons include:
Connection issue: Loose encoder cable plug, virtual soldering, or damaged shielding layer, resulting in signal interference or loss. Check the continuity of the cable and measure the resistance of each core wire with a multimeter to ensure there are no short circuits or open circuits; Replace the same type of cable with intact shielding layer and ground it to the driver end at a single point.
Physical damage: Scratches on the encoder and damage to the optocoupler caused by collisions, overload impacts, or bearing wear. If the shell is deformed or the bearing is stuck, the encoder module needs to be replaced and the zero position needs to be recalibrated.
Power supply abnormality: The encoder power supply voltage is unstable or exceeds the rated range (such as 5V ± 5%), and the driver output voltage needs to be measured to ensure compliance with specifications.
Environmental interference: Signal distortion caused by strong electromagnetic fields (such as frequency converters, welding machines) or high humidity. Stay away from interference sources, install magnetic rings, and keep the environment dry.
Overload protection: dual verification of load and parameters
Overload alarm is usually caused by excessive mechanical load or improper parameter settings, and needs to be investigated step by step:
Load assessment: Check if the transmission mechanism is stuck, if the bearings are worn, or if the load itself is overweight. For example, a certain automobile production line experienced an increase in friction due to insufficient bearing lubrication, triggering an overload alarm. The problem was resolved after replacing the bearings.
Parameter optimization: Setting speed and acceleration parameters too high may exceed the motor's load-bearing capacity. Parameters need to be adjusted according to the load characteristics, or reconfigured by referring to the equipment manual.
Power supply stability: Voltage fluctuations or insufficient power capacity can cause a decrease in motor output power. A voltage regulator needs to be installed and the power cord diameter needs to be checked to ensure it meets the current requirements.
Motor and driver status: Internal winding short circuit, power transistor damage, or poor connection of regenerative resistor (such as B2-B3 jumper wire detachment) may all cause overload. Use a multimeter to check the insulation resistance of the motor and tighten the wiring of the regenerative resistor.
Key points of security investigation
Power off operation: Before any maintenance, the power must be cut off to avoid the risk of electric shock.
Explosion proof compliance: Check whether the explosion-proof surface is corroded and whether the sealing ring is damaged to ensure compliance with GB3836 standard.
Professional support: For complex faults (such as damage to internal components of the encoder), it is recommended to contact the manufacturer or professional repair agency to avoid disassembling and causing secondary damage.
By systematically investigating the encoder signal chain and load parameters, and strictly following explosion-proof regulations, the root cause of faults can be efficiently located to ensure the safe operation of the system.