Bearing condition monitoring - Part 6
November 2006
Maintenance, Test & Measurement, Calibration
The last episode described the successful application of the shock pulse method on ultra slow rotating machines. We are now going to look at how the shock pulse method can help one to not only keep a handle on fan bearing operating and lubrication condition but also with some help protecting the fan from failure due to imbalance.
Most of the currently sold fan protection systems use a combination of overall vibration severity and in some cases temperature. Now if we look at the trend graphs (see Figure 1) we can see that shock pulse is used together with overall vibration severity in the horizontal and axial directions. Cooling water pressure and bearing temperature is also measured. If we look at the trend graphs from left to right we see that there was quite a peak in the horizontal vibration with corresponding smaller increases in temperature, axial vibration and both dBc and dBm. This is a typical case of fan imbalance. Due to the increased load of the imbalance on the bearing, the bearing temperature increased. The increased load (and temperature) also had an effect on the dBc, indicating reduced lubrication efficiency. After the fan was cleaned and balanced, everything returned to normal for a while. The next event was when the axial vibration increased. This was due to a problem on the suction side of the fan caused by an improperly adjusted draught valve. One notices a temperature increase but no change in the shock pulse level. This can be explained by the fact that the axial load carrying capability of the bearing was not reached.
Figure 1. Trend graphs
The next event shows a sharp increase in shock pulse level. This is typical of a failing bearing. If one looks at the change in vibration and temperature after replacement of the bearing one can notice a small change, however the method that showed the problem most prominently was SPM. One can thus see that for imbalance problems overall vibration is the best method to use, but for detecting bearing failures there is nothing that can touch SPM.
Further reading:
Engineering partnership delivers longer life for vibrating feeders in mining
Maintenance, Test & Measurement, Calibration
: OST-Africa’s combination of VISAM vibrating motors and advanced rubber mounting technology has helped Euro Sales achieve a 30 to 40% increase in component life on vibrating feeders at several major mining operations, with zero mount failures in the first 12 months.
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When oil can’t take the heat
Maintenance, Test & Measurement, Calibration
Unlike the slow ageing of oxidation, thermal breakdown is the sudden chemical collapse of a lubricant under excessive heat. Steven Lumley of WearCheck explains how it happens, where it strikes, and how oil analysis detects it.
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Mini data loggers for temperature and humidity monitoring
Maintenance, Test & Measurement, Calibration
Testo’s range of four compact data loggers covers temperature and humidity monitoring for storage, refrigeration and transport applications, with USB-C or Bluetooth connectivity and capacity for up to 16 000 readings.
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Alternative fuels for cutting, brazing, soldering and heating
Maintenance, Test & Measurement, Calibration
Bolt and Engineering Distributors, as an authorised distributor for the Harris Products Group, is helping South African industries transition from acetylene to safer, more cost-effective alternative fuels for cutting, brazing, soldering and heating applications.
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Rethinking corrosion protection in process plants
Omniflex Remote Monitoring Specialists
Maintenance, Test & Measurement, Calibration
Remote monitoring is changing how cathodic and anodic protection systems are managed in process plants, giving operators continuous visibility of corrosion protection performance and enabling more proactive maintenance decisions.
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Installation safety tester
Vepac Electronics
Maintenance, Test & Measurement, Calibration
A combination measuring device for testing electrical installations, offering safety tests including RCD, voltage, loop, low-resistance, earth resistance and insulation checks via a 3,5-inch TFT colour display.
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Bringing predictive maintenance to the next level in the pulp and paper industry
Maintenance, Test & Measurement, Calibration
ennomotive has launched an international competition seeking innovative predictive maintenance solutions for conveyor belt systems, addressing a real operational challenge faced by pulp and paper company CMPC.
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Vibration sensor with CANopen interface for mobile machines
ifm - South Africa
Maintenance, Test & Measurement, Calibration
ifm’s 3-axis VMB301 condition monitoring sensor integrates into the vehicle network via CANopen, delivering real-time bearing, vibration and temperature data to help mobile machines avoid costly damage and downtime.
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Linear regulated 2-channel laboratory power supply
Vepac Electronics
Maintenance, Test & Measurement, Calibration
Vepac Electronics offers a dual-channel laboratory power supply built for safe, precise testing in laboratories and workshops.
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When oil gets old
Wearcheck
Maintenance, Test & Measurement, Calibration
WearCheck explains how oxidation breaks down lubricating oils over time, and how routine oil analysis can catch the warning signs before equipment failure.
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