Regarding the fixation of handheld vibration testers to equipment
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This post was last edited by Bai Yunfan on 2016-2-17 at 12:18. When using a handheld vibration tester for data acquisition (such as with piezoelectric acceleration sensors), there are generally five ways to secure them: 1. Permanent magnetic base； 2. Needle-handheld pressing type ； 3. Fix with beeswax ； 4. Stick it with adhesive ； 5. Fix with threads. In my opinion, different fixing methods certainly affect the measurement accuracy of data across various vibration frequency bands. What I would like to verify is that for the various connection methods mentioned above, aside from the fifth one, which frequency bands are generally suitable, and which frequency bands should be avoided? For example, I estimate that the failure frequency of a pump is around 1200–1500 Hz; so which type of fixation should or must I choose? Additionally, motors all have an iron casing, whose main function is to help dissipate heat from the motor. However, the rigidity of this housing is very poor; it is certainly not practical to use it to measure the vibration behavior of motor bearings. So, how is it done in actual work? Surely one wouldn’t actually remove the motor’s casing just to measure the bearing vibration at the free end, right? Thank you!
Use the magnetic base if it is available; otherwise, press it by hand
I can only say that your vibration detector isn’t of high quality, haha ;P The one I bought before came equipped with a probe, a magnetic base, and beeswax.
Today I borrowed from a colleague a textbook titled \"How to Implement Effective Condition Monitoring Programs Using Vibration Analysis, Analysis I\", written by Technical Associate of Charlotte, P.C. (2006 edition). This issue was mentioned in Chapter 4.3. For Stud Mounting, tests have shown that the natural frequency of a certain type of Stud Mounting is 1,900,000 CPM, with a maximum testable frequency of 975,000 CPM. If it is used to test vibration information above 50,000 Hz, the Stud Mounting connection method must be used. As for adhesives, it is necessary to ensure they are used correctly (if they are too thick, it will affect the effectiveness). Furthermore, too long a testing time can also affect the test results; frequencies above 12,500 Hz can be tested. It is typically used for measuring vibration frequencies below 9000 Hz ； Magnetic base connection. Most diagnostic tests (i.e., the more precise tests as opposed to the simpler ones) fall within the range of 2000–7000 Hz, which is also within the range of response frequencies for magnetic bases. If the frequency is higher than 15,000 Hz or even reaches 70,000 Hz, the magnetic base is ineffective; adhesives or nuts must be used for installation ； Quick-connect – I’ve never seen this before. This connection method is fine for routine testing of PMPs, but it is not suitable for vibration frequency testing above 7000 Hz ； With a handheld probe, testing is generally carried out only within the frequency range of 500–1000 Hz. This is the least ideal and least recommended method of connection; sometimes, its maximum response frequency is as low as 500 Hz.
The TV110 and VC63 bought from the factory really don’t work
The measurement point on the non-load side of the motor can be selected at the fixing bolt of the guard! I saw it in a book; I’ve forgotten the exact source!