Determine the 0 point for shaft displacement of Shaanxi Blower axial flow fans
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I have a question regarding motors equipped with fans: The Bentley probe for measuring shaft displacement is installed on the outside of the inlet side of the motor housing (it is screwed in using threads; its sensitivity is 7.8 V/mm, similar to that of vibration probes). 1. If the shaft is pushed towards the inlet side, should this be considered the 0 point? 2. If the shaft is pushed towards the inlet side and the gap is 500 um (the closer the probe is, the higher the reading on the positive side), should this be considered -250 um? 3. For turbines, I used the method described in step 2, but I pushed the shaft towards the outlet side. As for blowers, I’m not sure what to do. I would appreciate advice from those who are more experienced
The principle is the same, but adjustments in this area must be made in a timely manner in accordance with the requirements outlined in the equipment maintenance manual. For unclear points, consult the equipment manufacturer. Because the installation of this probe falls under the category of instruments; it requires adjustment and positioning carried out in collaboration between instrument specialists and mechanical technicians. Remember to implement it based on evidence, for reference only.
Basically, it is installed as described above, that is, the electrical zero-gap measurement method.
It should be +250um; I plan to install it closely against the working surface
1. Determine which side is the main thrust surface: In such load-bearing units, the side close to the air inlet is usually the main thrust surface. 2. Then define positive and negative displacements: Normally, it is defined as positive (positive displacement) when the rotor moves towards the main thrust surface ； 3. Determine the current position: Push the current shaft (rotor) towards the intake side, so that the rotor is in close contact with the main pushing surface (it is important to ensure this close contact). 4. Calculation: The computer will display a value of +250um, which is equivalent to +0.25mm. If measured using a multimeter, the feedback voltage from the preamplifier will be -10V + 0.25mm * 7.87V/mm = -8.0325V ≈ -8.03V. Extension: In the case of a turbine unit (that generates work), the side closer to the inlet side is the secondary thrust surface, and displacement toward the primary thrust surface is still defined as positive. The above are the standard practices; it is recommended to consult the manufacturer to ensure everything is in order.