Increased electric power consumption
A rise in consumed power under unchanged load is an early indication of declining equipment efficiency. The register contains 70 industrial-test cases; the median reduction in power consumption is 10 %.
The upper boundary of the range corresponds to units with a high degree of wear, whose initial consumption substantially exceeded the rated value.
Causes of increased consumption
Increased electric power consumption in industrial units is caused not only by a direct rise in friction forces, but also by a systemic decline in the overall efficiency of worn assemblies. The electric motor is obliged to compensate for the mechanical as well as the hydraulic and pneumatic losses of the equipment.
Mechanism of energy efficiency loss
- Reduction of volumetric efficiency (internal leakage). Loss of the initial geometry of the cylinder-piston group or wear of pump impellers results in reverse leakage of the working medium. Consequently the unit (a compressor, for example) requires considerably more time and operating cycles to build up the rated pressure in the system.
- Rise in mechanical losses. Wear of bearing assemblies and an increase in operating clearances in toothed gearings disturb the kinematics and directly raise the resistance to rotation.
- Cumulative rise in power. To perform the same volume of useful work under reduced efficiency, the electric motor begins to draw a continuously higher active power.
Diagnostics and failure prediction
Standard regulations for condition monitoring assess a set of parameters: radial and axial clearances, shaft runout, vibration velocity level, acoustic emission and lubricant temperature.
Within this set, consumed current acts as an integral indicator. It registers the mathematical sum of all developed defects: a rise in current unmistakably signals that the decline in efficiency and the mechanical losses have reached a critical level, even if the unit has not yet entered the stage of evident failure.
Idle running and operation under load
The relative reduction at idle running is higher owing to the smaller absolute magnitude of consumption. Across the body of test reports the divergence is insignificant: 11.0 % at idle running (21 reports) against 10.3 % under load (26 reports).
Treated assemblies
Current and power were recorded at the drive; the treatment was applied to the friction assembly: machine tool bearing supports, compressor cylinder-piston group, gearbox toothed gearing.
Equipment types
Test reports
Fifteen test reports with the maximum recorded reduction out of 67 containing a direct measurement of current or power. The full list is given in the catalogue.
| ENTERPRISE | YEAR | CHANGE | PARAMETER MEASURED |
|---|---|---|---|
| Rosava JSC | 2005 | ↓ 42.6–59.7% | power consumed per machine work cycle, 1.566–3.098 → 0.853–1.649 kW |
| KRAST JSC, Stavropol | 2003 | ↓ 33–37% | drive motor current at operating modes, 180–245 → 120–160 A |
| Barnaulsky Instrument JSC | 2005 | ↓ 31.8% | current draw of the compressor head, 22 → 15 A |
| SKLO LLC | 2001 | ↓ 28.6% | no-load current draw, 210 → 150 A |
| Chugunoleene Invest 97 AD | 2002 | ↓ 25% | power consumption of the hydraulic unit, current under load 31–33 → 24 A |
| Tomakovskiy Expanded Clay Gravel Plant | 2007 | ↓ 20.5% | no-load current draw, bowl drive No. 1, 44.0 → 35.0 A |
| JSC Gomelsteklo | 2001 | ↓ 20–27% | gearbox drive motor current, 50–55 → 40 A |
| Stoilensky GOK | 2003 | ↓ 18.4% | compressor current draw, 19 → 15.5 A |
| CJSC MKF | 2001 | ↓ 18% | phase current of the drive electric motor, 110 → 90 A |
| KhTsNTEI JSC, Kharkiv | 2005 | ↓ 18–23% | drive current on all three phases, 10.4–11.0 → 8.0–9.0 A |
| KRISTAL AD, Plovdiv | 2002 | ↓ 16.7% | current draw of the conveyor drive, 3 → 2.5 A |
| DKS MZU “Smena” | 2003 | ↓ 16.7–29.7% | current on all three phases under load, 10.2–12.8 → 8.5–9.0 A |
| GAO Chernomorneftegaz | 2003 | ↓ 16.7–29.7% | current of the K-80-60-160 pump under load, 10.2–12.8 → 8.5–9.0 A |
| PGT “KHIMPROM” | 2001 | ↓ 16.7% | no-load current draw, 120 → 100 A |
| Dneprometiz JSC | 2001 | ↓ 16% | current draw, 25 → 21 A |
All 70 cases in the catalogue →
Documents of the cases with a direct measurement: plant commission reports — 41, signed test protocols — 26, other documents — 0; the document type is stated on the case card.
Limits of data applicability
- Applicability. The figures relate to the equipment and operating conditions of the enterprises named in the reports; on a different unit the result depends on initial wear, load and oil.
- Source document. A scan of the original report is published under every case; if the card and the scan disagree, the scan is authoritative.