Electric motors are connected to various rotating equipment, such as air compressors, pumps, fans, blowers, conveyors, etc. The efficiency of motors can be significantly improved by following these basic guidelines
Management and control
- Operate motors in the range of 75%–80% load for maximum efficiency. Avoid underloading of the motors
- Stop motor-driven equipment when not in use or during idle operation
- Ensure balancing of voltage in all three phases of motors for optimum performance
- Ensure operating power factor close to unity
- Ensure adequate ventilation of motors to avoid overheating
- Use direct online (DOL) starters for motors up to 5 hp, star-delta type starters for 5–20 hp motors, and soft starters for motors with more than 20 hp capacity
- Avoid rewinding of motors more than two times. Replace rewound and standard motors with energy-efficient motors (IE3 motors)
Measurement and recording
- Electricity consumption, voltage, current and power factor daily
- Motor body temperature, vibration, rpm, etc., every month
Maintenance and inspection
- Inspect for wear and tear of foundation bolts, shaft, and bearings quarterly
- Check proper tightness of electrical cables connecting motor terminals to avoid any arcing and short circuit quarterly
- Inspect and maintain motor-driven equipment quarterly to reduce mechanical losses occurring in electric motors, power transmission units, and machines that apply loads to the motors, for example, the industry shall ensure proper tension of belts to minimize transmission losses
- Calibrate instruments as per the recommendations of the suppliers to ensure reliability and maintain the accuracy of data
- Monitor and maintain lubricant oil level daily
Other recommendations
- Install energy-saving measures, such as VFD, motors with permanent magnet slip power recovery systems, fluid couplings, etc., for variable load applications to minimize energy consumption.
- Use cogged v-belts instead of flat v-belts for belt-driven motor applications
- Install IE3 motors for various applications
- Maintain unbalanced voltage within 1%–3%
Energy efficiencies of IE3 motors (Premium)
| Rating (KW) | 2 pole | 4 pole | 6 pole |
| .37 | 75.5 | 73.0 | 71.9 |
| .55 | 78.1 | 78.0 | 75.9 |
| .75 | 80.7 | 82.5 | 78.9 |
| 1.1 | 82.7 | 84.1 | 81.0 |
| 1.5 | 84.2 | 85.3 | 82.5 |
| 2.2 | 85.9 | 86.7 | 84.3 |
| 3.7 | 87.8 | 88.4 | 86.5 |
| 5.5 | 89.2 | 89.6 | 88.0 |
| 7.5 | 90.1 | 90.4 | 89.1 |
| 11 | 91.2 | 91.4 | 90.3 |
| 15 | 91.9 | 92.1 | 91.2 |
| 18.5 | 92.4 | 92.6 | 91.7 |
| 22 | 92.7 | 93.0 | 92.2 |
| 30 | 93.3 | 93.6 | 92.9 |