Imbalance

不平衡

Per DIN ISO 1), an imbalance is present in a rotating system if forces or oscillation movements are transferred to the bearing as a consequence of imbalanced centrifuges.

Imbalances on a rotating structure not only cause forces on the bearing and foundations, but also oscillations in the machine. These oscillations have a harmonic nature, with the excitation frequency corresponding to the rotary frequency of the imbalanced rotor.

根据 DIN ISO1)标准，如果由于离心机不平衡而导致力或振荡运动传递到轴承，则旋转系统中存在不平衡。

旋转结构上的不平衡不仅会导致轴承和基础上的力，还会导致机器振荡。这些振荡具有谐波性质，其激励频率与不平衡转子的旋转频率相对应。

Alignment errors

对中误差

The main function of coupling is to connect 2 shafts in order to achieve a statically determinate complete system. In addition to transferring torque, couplings also offset misalignment (radial, axial, angular) to a certain extent. However, if the misalignment exceeds the compensation capability of the coupling, additional loads such as increased bearing forces, forced shaft deformation and axial forces occur for the machine elements involved.

Oscillations have a harmonic nature and are bound to the rotary frequency of the misaligned shafts and the multiples of this frequency. Misalignment can be measured using the rotary frequency of the misaligned part or its harmonic oscillations.

联轴器的主要功能是连接两个轴，以实现一个静态确定的完整系统。除了传递扭矩，联轴器还能在一定程度上抵消不对中（径向、轴向、角向）。然而，如果不对中超过了联轴器的补偿能力，则会对所涉及的机器元件产生额外的载荷，如轴承力增加、轴的强制形变和轴向力。

振荡具有谐波性质，并与未对准轴的旋转频率和该频率的倍数有关。可以使用未对准部件的旋转频率或其谐波振荡来测量对中误差。

Impacts

冲击

Foreign objects as well as loose or colliding parts can cause shocks between rotating and stationary parts. These shocks repeat periodically once or several times each time the shaft revolves.

The frequency of these shock repetitions corresponds to the rotary frequency of the shaft or its harmonic frequency.

异物以及松动或碰撞的部件可能会在旋转部件和静止部件之间造成冲击。每当轴旋转时，这些冲击会周期性地重复一次或几次。

这些冲击重复的频率对应于轴的旋转频率或其谐波频率。

Roller bearing damage

滚子轴承损坏

Most bearing damage results from changes on the surface (pitting). By rolling over the damaged area on the inner ring, outer ring, cage or rolling element, pulse-shaped shocks occur that make the bearing structure and its components vibrate.

Each of these shocks appears in the oscillation signal through the typical course of a shock sequence. Characteristic values can be obtained from these measurements that give an indication of the condition of the bearing.

The excitation frequency on the inner ring, outer ring, cage and roller bearing damage is specified by the bearing manufacturer.

大多数轴承损坏是由于表面的变化（点蚀）造成的。通过在内圈、外圈、保持架或滚动体上的损坏区域滚动，发生脉冲状冲击，使轴承结构及其部件振动。

每一个冲击都通过冲击序列的典型层出现在振荡信号中。从这些测量值中可以得到轴承状况的特征值。

Magnetic induction

磁感应

A rotating magnetic field causes counterforces in the stator of the machine. This electric magnetic stimulation often causes oscillations on the electric motors that are hard to detect.

Inverters also often lead to an inference of oscillations, the cause of which is of an electrical magnetic nature.

旋转的磁场在机器的定子中引起反作用力。这种电磁激励往往在电动机上引起难以察觉的振荡。

变频器是经常导致振荡的原因，其原因是电磁特性。

1) 1925 DIN ISO 1925: Issue: 1996-11 Mechanical oscillations - Balancing technology - Terms (ISO 1925:1990 + AMD 1:1995)

振荡的原因： - Causes of oscillations: