【Weekly Topic】Topics on dynamic balancing
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This post was last edited by zxf760718 on 2016-1-26 at 15:06. Dynamic balance and static balance are inspection items that are often encountered in the management of rotating equipment; different methods should be used depending on the situation, otherwise it leads to both wasted effort and money. This brings us to this week’s topic: Which types of equipment in rotating equipment management require dynamic balance, and which ones only need static balance? We welcome everyone to actively participate in the discussion! 【Collection of Essential Knowledge for the Mechanical Forum】http://bbs.hcbbs.com/thread-1389197-1-1.html Topics for each week and daily questions are being sought (prizes available for participation) http://bbs.hcbbs.com/thread-1373282-1-1.html Summary post of weekly topics: http://bbs.hcbbs.com/thread-1404940-1-1.html Starting today, the Mechanical Forum is bringing wealth to all its members http://bbs.hcbbs.com/thread-1489563-1-1.html Go and claim your wealth now – the distribution has begun!
The rotor is rusted and corroded; there is high vibration, so dynamic balancing is required
Mixers, fans, centrifugal pumps, vacuum pumps, compressor pulleys, and more
Rigid rotors only require low-speed dynamic balancing, while flexible rotors need high-speed dynamic balancing.
For equipment managed under dynamic equipment management, which devices require dynamic balancing, and which ones only need static balancing? We welcome everyone to actively participate in the discussion! The condition for static equilibrium is that the sum of the inertial forces acting on the structure is zero; in other words, the centroid of the rotor lies on the axis of rotation. The condition for dynamic equilibrium is that both the inertial forces and the inertial moments are zero
The rotor of rotating equipment needs to be dynamically balanced.
Selection between static and dynamic balancing: As long as the requirements of the rotor’s intended use can be met through static balancing, there is no need to resort to dynamic balancing; and if dynamic balancing is possible, then there is no need for both static and dynamic balancing. It is mainly determined by the ratio of the rotor’s diameter D to the distance b between its two opposite faces (according to API610, 8th edition). For rotors that are only required to be in static balance, the following conditions apply: 1) For single-stage and two-stage pumps, when the operating speed is less than 1800 revolutions per minute, it is sufficient to ensure only static balance, regardless of whether D/b < 6 or D/b ≥ 6. However, if dynamic balancing is required, it is necessary to ensure that D/b < 6; otherwise, only static balancing can be performed. 2) For the rotors of single-stage and two-stage pumps, when the operating speed is ≥ 1800 revolutions per minute, static balancing is sufficient if D/b ≥ 6. However, the remaining unbalance after balancing must be equal to or less than 1/2 of the allowable unbalance. If dynamic balancing is required, it is necessary to check whether the balance of the two correction surfaces can be achieved separately on a balancing machine; if not, only static balancing can be performed. 3) For some rotors such as open impellers, if end support cannot be achieved, only static balancing is sufficient. Since the ends cannot provide support, a cantilever structure is necessary; as a result, performing dynamic balancing on a balancing machine is very dangerous, and single-sided (static) balancing can only be carried out on a balancing stand.
1. For single-stage and two-stage pump rotors with an operating speed of >=1800 r/min, D/b