Blowers and fans are equipment used for ventilation, aeration, exhaustion, cooling and drying in various production processes in the most varied industries.
The fans are subject to forces generated by their operating speed, static pressures and system arrangement. These forces, called operational forces, cause forced vibrations and can originate from the rotating parts themselves. Unbalanced fan wheels and driving pulleys are examples of forces that can cause unbalance and misalignment. Another example is the axial load on the fan bearings, which is mainly generated by the negative static pressure at the inlet of the fan blades.
Due to the process in which this type of system is used, the most common fault modes are: unbalance, misalignment, eccentric pulleys, looseness and belts wear and structural looseness, identified at low frequencies. Also, some bearing problems, especially premature wear and tear generated by the fault modes mentioned above, can occur. But it is possible to work with the identification of advanced stage 3 bearing, where the frequencies BPFO, BPFI, BSF and FTF, occur in values below 1 kHz.
The DynaLogger TCA+ model with its spectrum range up to 1 kHz, is useful to identify these faults. However, in order to identify lubrication faults, or even electrical faults connected to the motor rotor or stator, it is indicated the DynaLogger HF model, due to its greater frequency range of up to 6.4 kHz.
It is important to mount DynaLoggers on all bearing housings or rigid parts for effective monitoring. Avoid mounting sensors on flexible surfaces, on curves or that have localized resonance such as protective covers and fins.
Table1 - Typical fault frequency and its causes