Looking for advice on designing a Dynamic Vibration Absorber (DVA) to reduce high vertical motor vibrations of 25mm/s rms @ 7HZ. The motor is connected to a gearbox and powers a fan. Any assistance would be greatly valued. Thank you, Rana Ali.
If you are seeking guidance on designing a Dynamic Vibration Absorber (DVA) to combat high vertical motor vibration of 25mm/s RMS at 7Hz, then let us help you. The motor is connected to a gearbox and operates a fan. Your support in this matter is greatly valued. For more information, visit www.midlandsrc.com and connect with Dave Reynolds.
Looking for someone to create a Dynamic Vibration Absorber for a motor to reduce its high vibration levels. I have all the necessary information related to the motor. Your assistance in designing and manufacturing this DVA would be greatly appreciated. Contact me at your earliest convenience. Thank you. Rana Ali Visit www.midlandsrc.com for more information and resources on engineering solutions.
In the past, I encountered a similar issue with a vertical motor driving a diaphragm pump through a gearbox, resulting in excessive vibration levels due to resonance. After re balancing the rotor, the vibration levels decreased significantly, providing a practical solution to the problem. This occurred with one of two newly installed pumps. ------------------------------ Alex ------------------------------ Original Message Original Message: Sent: 07-27-2023 05:46 From: Rana Ali Subject: DVA design Can anyone assist in designing a Dynamic Vibration Absorber (DVA) to mitigate high vertical motor vibrations of 25mm/s rms @7HZ? The motor is linked to a gearbox and operates a fan. Your input would be greatly appreciated. ------------------------------ Rana Ali ------------------------------
Attached are two spreadsheets for calculations. Please review them. - Alex
Rana, it sounds like you're tackling quite a task there! In my experience, the trick with DVAs is fine-tuning them to match the frequency of the disruptive vibration, in this case, your 7Hz. You'll also want to consider the mass ratio between the DVA and the vibrating system. Too small, and your DVA might not adequately absorb the vibration; too large, and you might inadvertently introduce more problems by overcompensating. Experimentation will probably be your best friend here. Good luck with your project!
First, it is critical to understand the cause of the problem, so I recommend performing a full vibration analysis if you haven't already. To design an effective DVA, consider using resonance tuning. Your DVA's natural frequency should match the known troublesome frequency you mentioned (7Hz). Proper damping is also crucial, as overly damped absorbers can transmit rather than absorb vibration. Don't forget about the mass ratio between your absorber and the system since an inadequate mass could result in system instability. It can be a complex process, so professional help such as a mechanical engineer specializing in vibration control could be beneficial.
Hi Rana, it sounds like a challenging situation. From what I understand, you could initially focus on determining the natural frequency of the system by using the mass-spring-damper model. This could potentially aid you in designing a DVA with its natural frequency somewhere close to 7Hz, which is your problematic vibration frequency. Additionally, consider using rubber mounts for damping as they're good at absorbing and isolating vibration. Also, if possible, check the alignment of the motor/gearbox/fan connection, as even a slight misalignment can create large vibrations.
Hey Rana, for a dynamic vibration absorber to effectively mitigate those 25mm/s rms vibrations at 7Hz, consider tuning the absorber's natural frequency to be slightly below 7Hz to maximize its effectiveness. Using a spring-mass system could work well, but pay close attention to the damping characteristics to ensure it can handle the energy without introducing excessive phase lag. Also, you might want to analyze the system's overall mass distribution since the positioning of the DVA can greatly affect performance. Good luck with your design!
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Answer: 1. What is a Dynamic Vibration Absorber (DVA) and how does it work to reduce motor vibrations? - A DVA is a device designed to reduce vibrations by dynamically absorbing and dissipating energy. It consists of a mass-spring system tuned to the specific vibration frequency, effectively counteracting the motor vibrations.
Answer: - The specifications for a DVA, such as mass and stiffness, are determined based on the frequency and magnitude of the motor vibrations. In this case, with vibrations of 25mm/s rms @ 7Hz, the DVA needs to be designed to resonate at this frequency and effectively dampen the vibrations.
Answer: - When designing a DVA for such a system, it is important to consider the weight distribution, mounting location, and structural integrity to ensure effective vibration reduction without interfering with the operation of the gearbox and fan.
Answer: - Best practices include conducting a thorough vibration analysis to accurately identify the vibration characteristics, selecting appropriate materials for the DVA components, and ensuring proper installation and tuning to achieve optimal vibration reduction performance.
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