The heat inside the motor terminal cannot be measured by the external temperature of the motor terminal. The design temperature rating in the technical specification is related to the hottest area in the motor winding, rather than to heat transfer on the outer surface of the motor terminal. Heat transfer is more related to the size, quality and design of the body frames. Ribbed or smooth frames, open and closing frames vary greatly in different motor designs. The frame surface of any motor terminal is composed of hot spots, which is usually directly related to the internal and external air circulation mode. The external temperature of the motor terminal is almost irrelevant to the possible thermal problems inside the motor terminal.

Motor winding:

The specified operating temperature of motor terminal is related to the winding temperature. Insulation is used to separate electrical components to prevent short-circuit abnormalities, resulting in winding burnout and motor terminal failure. Motor terminal insulation includes magnetic wire coating for insulating coil lines. Tank units and phase insulation are usually made of high-strength polyester board to provide ground protection and moisture resistance, all of which are necessary. However, the motor terminals cannot be protected from other factors, such as vibration, chemical pollution and abrasives that may occur in the operating environment of the motor terminals. The motor winding is designed to operate at a specific temperature to ensure an average service life of 20,000 hours. Temperature standards are set according to the heat insulation levels.

Environmental considerations:

Understand the location, installation mode and operating conditions of motor terminals. Motor terminals need to be installed with a solid base to reduce the possibility of dislocation and increase possible friction and vibration. These factors can lead to motor terminal strain, resulting in overheating. Make sure there is enough air flow around the motor terminals. If the motor terminals are not sealed, there will be no particles in the air. Keep the motor terminals away from direct airflow of the heater or air conditioner and fenestration area where humidity or precipitation can easily enter.

Use a suitable housing for the working environment of motor terminals. For example, if your environment is filled with dust and debris, which can easily enter the motor terminals and block the engineering, then the ventilation housing for airflow cooling may be the wrong method. If the motor terminals are exposed to direct sunlight most of the day, then sealed housing may be the wrong choice. High altitude also affects motor terminals because thin air provides less cooling.

Clean energy is just as important as the other factors mentioned here. Many electronic drives focus on reducing harmonics and providing good power quality. However, if the voltage imbalance between phases exceeds 2%, the winding may be damaged. It can also be considered to operate the motor terminal at about 80% of the recommended load to compensate for changes over time. Another problem is that the voltage is too low, and may cause more current to be generated from the motor terminals. Similarly, long-term operation of motor terminals under high voltage may saturate the motor terminal core and lead to overheating.

Safety features:

There is little reason to worry about overheating, when correctly installed and applied motor terminals under standard conditions. This does not mean that unexpected environmental changes will not happen. After all, the equipment will be aged and misused, and may be subject to abnormal impact or vibration in other areas of the system. This is why application engineers often install overload protectors in motion system design, such as resistance temperature devices or thermocouples. This method can ensure that motor terminals are offline before catastrophic failure.

If your safety equipment continues to turn off motor terminals, motor terminals may be improperly sized and overheated. A quick check of the current consumption on the motor terminal will determine whether the motor terminal works normally. Check the current reading according to the specifications listed on the motor nameplate rating to ensure that it operates within the range.