Avoid Frequent Starting and Stopping of the Motor
Frequent starting and stopping will have a significant impact on the life of the three-phase motor, mainly because each start causes the motor to consume a large starting current, generally 4–7 times the rated current. This sudden large current generates enough heat, which will damage the winding insulation and eventually reduce its lifespan. Frequent starting and stopping can severely reduce the motor’s lifetime by more than 30%; a motor expected to last 10 years may actually last less than 7 years.
It also increases mechanical wear, particularly in heavy-load applications such as automated assembly lines in manufacturing and lifting equipment with frequent starting and stopping. These applications should control the number of motor starts and stops to be no more than four times per hour to ensure transmission devices and bearings last longer. According to analysis data from a renowned motor manufacturer, if the start and stop frequency is greater than 10 times, it can result in more than a 50% increase in maintenance costs of the motor. Equipment such as frequency converters can change the starting speed of a motor so it will safely enter into working condition. This not only reduces the power-up current but also extends the life of the transmission system. If the production lines are usually started and stopped, it may be an idea to rearrange the process flow in such a way that we reduce the number of no-load motor starts.
Keep the Motor Temperature Stable
The lifespan of a three-phase motor is directly related to how well it manages temperature. Too high a temperature causes the motor winding insulation materials to age and deteriorate, lowering its efficiency. In general, every time the motor temperature rises by 10°C, the life of winding insulation materials is reduced by half. Once the motor temperature exceeds 80°C, its service life will be reduced by at least 40% compared to normal conditions, thereby increasing the maintenance and replacement costs for corporate equipment.
In order to dissipate the motor’s heat, you usually use air cooling or water cooling systems. For higher power motors, a closed-loop water cooling system is even better and can dramatically improve cooling results. Air cooling systems are mainly used for small and medium-sized motors, which have the advantage of low cost and better economy. A superior motor supplier displayed the most recent air cooling technology at an industrial expo, stabilizing the surface temperature of a 1,550 rpm motor at 65°C during operation, greatly extending its service life. Dust and debris accumulation undoubtedly affects the heat dissipation effect, leading to higher temperatures of the motor body. In the logistics and warehousing industry, some enterprises do not clean their ventilation openings at all, leading to motors overheating and stopping, with downtimes lasting hours; they say that the losses from this can reach up to $300,000 annually. The motor temperature can be reduced by about 10% if we clean the ventilation slots and heat sinks regularly, which is also beneficial for the service life of the equipment.
Regular Lubrication
Especially with equipment that works under high load for long periods, regular lubrication is essential to ensure the normal operation of a three-phase motor. Without lubrication, bearings wear faster, friction increases, and a whole host of other problems like overheating and efficiency loss occur. According to statistics by ISSA (Industrial Equipment Maintenance Association), more than half of motor failures are related to improper lubrication, and regular lubrication can reduce failure rates by over 30%. The lubrication cycle of bearings usually differs due to the load and working environment of the motors. Comprehensive lubrication maintenance every 2,000 hours of operation is a common recommendation. In high-temperature or high-humidity environments, the cycle should be shortened to 1,500 hours.
In addition to that, determining the right type of lubricating oil is also very important, since motors of different models and power require lubricating oils with different viscosities and performance. In heavy industrial applications, high-viscosity mineral oils or full synthetic lubricating oils are used to guarantee good lubrication performance under conditions of high temperature and heavy pressure. Similarly, the lubricating oil in use should be checked regularly for rust, aging, and residue content to prevent contamination or aging. Do not forget about proper lubrication procedures. The motor will not have abnormal problems if it is used with appropriate lubrication levels; either excessive or insufficient lubricant could lead to issues. Adhering to the appropriate amount and method of lubricant application is a great step in avoiding these risks.
Motor Dustproofing and Moisture-Proofing
How to effectively implement dustproofing and moisture-proofing for three-phase motors used in harsh environments? Dust and moisture intrusion would not only create an internal short circuit of the motor but also cause corrosion of windings and bearings, reducing the motor’s service life. According to statistics from the American Electrical Manufacturers Association, about 30% of industrial motor failures are caused by dust and moisture, and effective dustproof and moisture-proof measures can reduce these failures by more than 50%. The choice of protection level is crucial, especially for motors that are working in dusty and humid conditions for a long time. Therefore, in man-made panel factories, as long as the motor insulation is above IE (B) and has a rating of IP55 or higher, dust will not enter inside the motor casing and windings will be prevented from becoming damp. For outdoor equipment, it is advisable to choose a motor with an IP65 protection standard to protect its operation against wind and rain.
