Hello, We have hoist structures in our PTMS that are supported by powerful 18.5 kW motors. These motors are equipped with an electromagnetic disc brake that is activated by a BME 1.5 rectifier. Recently, we encountered a problem where the disc coils were burned, and we are struggling to identify the root cause of this issue. The brake rectifier is connected directly to a 3*400V line through a circuit breaker rated at 3.5-5A, as well as a contactor that triggers its activation. We are curious about the potential reasons behind a disc brake burning out in this scenario. Our motor operations are overseen by a VFC, with brake activation controlled by a PLC. Thank you for your valuable insights and time.
Alij mentioned an issue with hoist structures in their PTMs supported by Sew 18.5 kW motors. These motors come equipped with an electromagnetic disc brake activated by a BME1.5 rectifier. After experiencing burnt disc coils, the cause of the problem remains elusive. The brake rectifier is linked directly to a 3*400V line through a 3.5-5A circuit breaker and a activating contactor. What factors could be contributing to disc brake burnout? The motors are controlled by a VFC, with brake activation managed by a PLC. It is crucial to consistently monitor the air gap, as wear on the brake disc can lead to increased air gap that requires adjustment. When replacing a burnt coil, consider replacing the rectifier as well. By adhering to proper maintenance practices for brake motors, instances of failure have significantly decreased.
Have you confirmed that the coil is specifically designed for direct current rather than alternating current? Connecting an AC coil to DC power can lead to serious damage. It seems unusual to have a brake connected to 400V DC.
To ensure optimal performance and safety, it is essential for the power to the brake coil to be DC. It appears that a 3-phase full-wave rectifier is used to power the brake coil, with most brake modules automatically reducing power to prevent coil overheating. It is important to avoid applying 3-phase or any AC power to the brake coil to prevent damage and ensure proper functioning. Regular inspection of the brake system is crucial to ensure the brakes are still effective in holding the load when the power is off. It is recommended to check if the disk can fully retract to prevent coil overheating. Make sure that the brake coil is energized to release the brake, as the spring should engage the brake when the power is off. Proper maintenance and inspection of the brake system can prevent potential issues and ensure smooth operation. In my experience designing and building crane systems, I have observed minimal wear on the brake pads even after over 5 years of constant operation. To further extend the lifespan of the brake system, it is advisable to only engage and release the brake when the motor is stopped, unless in the event of a power failure. Regular maintenance and careful operation can help prolong the life of the brake system.
It is important to be able to sense the engagement and disengagement of SEWs, as they play a crucial role in operation. Despite not working with SEWs for a while, I recall overseeing over 100 units in the plant without encountering any malfunctions. These SEWs were designed to be fail-safe, primarily serving to hold rather than stop operations, as Gary mentioned in case of a power outage.
From my experience, disc brake coil burnout could occur due to several reasons. One possible cause could be excessive current in the coil, which mostly happens when the rectifier or controller malfunctions, leading to overshooting of required voltage. So, you might want to have your BME 1.5 rectifier inspected. Also, consider checking on your PLC's brake control settings, to ensure they're working correctly and not causing any anomalies. Another potential culprit could be frequent starts, stops, or reversals. If your operations demand such action frequently, the brake disc coil could experience overheating, subsequently leading to damage. Regular preventative maintenance can help you identify issues before they lead to breakdowns.
Hi there, There could be numerous reasons as to why the disc coils are burning out. One plausible cause might be due to excessive heat from overloading or overuse. If the brake is being excessively operated, this could cause overheating, leading to burned coils. Also, you may want to examine the duty cycle of the braking operation - is the brake frequently engaged and released? That might also generate a lot of heat which might be damaging to the coils. Simultaneously, it's crucial to consider electrical issues that can lead to the coil being overheated. This could be due to a short in the coil windings, or an issue with the voltage supplied to the coil. Have you checked if the rectifier is supplying the correct voltage and isn't malfunctioning or miswired? Lastly, it's a good idea to check the insulation resistance of the coil windings, a low resistance could lead to current leakage and excessive heat. You'd need to use a megger for that, if available. It's always a good approach to assess schematic, mechanical and electrical connections for any discrepancies.
It sounds like a complex situation you're dealing with. In my experience, a burned-out disc coil could be caused by a few things. Overheating due to excessive current passing through the coil might be one of those factors. It's crucial to ascertain whether the rectifier is working correctly and delivering the right reduction in voltage to the coil. If that seems to be fine, then the fault could possibly be in the PLC controlling the activation and deactivation of the brake. Incorrect activation and deactivation intervals can cause the brake to engage too frequently or for too long, causing the coil to overheat. I would recommend starting with checking these controls as well as the proper functioning of the rectifier. Lastly, don't rule out the possibility of a fault in the coil itself, it's less common but it does happen. I hope this helps!
The issue you're describing could be resulting from overheating. This tends to happen when the brake is engaged for extended periods, leading to excessive current passing through the coils. It's also possible that the voltage of your power source might be too high, which would also contribute to overheating. I strongly suggest you check your brake timing - an incorrectly timed braking system might cause the motor to work against the brake. Additionally, verify your circuit breakers and contactors are functioning properly. Faulty wiring could also be an issue, as it could lead the brake to be energized for longer than intended. Lastly, always ensure your brake coils are rated for your power supply. If they’re not, they'll likely burn out.
It sounds like you're dealing with quite a complex setup! One potential reason for the disc coils burning out could be an electrical overload or insufficient current limitation, especially if the breakers or contactors aren't sized appropriately for the motor's demands. Additionally, if the rectifier isn't functioning correctly or if there's an issue with the VFC's settings, that could lead to voltage fluctuations that might damage the brake coils. It’d be worth examining the operation cycles of your motors, as excessive or improper use can also contribute to overheating. Have you checked the ambient temperature and cooling mechanisms around the brakes? Sometimes, inadequate cooling can exacerbate these issues, even if everything else seems in order.
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Answer: - The disc brake burnout in this scenario could be attributed to factors such as electrical overload, mechanical issues, incorrect voltage supply, or faulty components within the braking system.
Answer: - The electromagnetic disc brake system in hoist structures with 18.5 kW motors is activated by a BME 1.5 rectifier, which is connected to a 3400V line through a circuit breaker and a contactor for activation control.
Answer: - The Variable Frequency Drive (VFC) oversees motor operations, while the Programmable Logic Controller (PLC) controls the activation of the brake system, ensuring precise and efficient braking functionality.
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