Some factors that affect the temperature rise of the motor may not be noticed!

In the previous topics, we talked about the temperature rise of the motor, and the focus was on the temperature rise of the motor winding. It is obviously unreasonable to talk about the temperature rise of the motor winding in isolation. Not every factor related to the winding can be paid attention to, but it has a particularly great impact on the temperature rise of the motor winding. The issues we talk about below are all based on the premise that the winding design, iron core and other components are in compliance.

1. Problems with the motor wiring system
During the analysis of motor fault cases, it was found that the welding of the motor wire and the main wire, the connection of the wire and the terminal, the connection of the terminal and the terminal board, the diameter of the core, etc., may cause heating of the wiring system and cause directly affects the temperature of the motor winding, thereby affecting the motor temperature rise. When this kind of problem is serious, it will cause the motor to be partially burned out in a short period of time, and may also directly spread to the stator winding.

2. Rotor heating problem caused by defects in cast aluminum rotor
This problem ly occurs in motors with relatively large power and relatively long rotors. This problem is due to casting defects in the motor rotor itself. For example, the rotor guide bars have thin or broken bars. The rotor will heat up seriously during the operation of the motor. Heat will naturally dissipate to the motor windings, causing an increase in temperature rise.

3. Problems caused by bearing systems
Under normal circumstances, the temperature of the motor bearing system is controlled at a relatively stable limit, generally controlled at 95 degrees. The actual inspection process found that, except for motors operating in special high-temperature environments, the bearing temperature of motors is below 70 degrees, if the temperature is too high, the grease may fail, causing the bearing to fall apart and lock. When the temperature of the bearing system is high, its heat will also be conducted to the motor windings. When the temperature of the windings rises, it will have a negative impact on the bearing system. The superposition of the two problems will cause problems in the motor in a short period of time.

4. Scanning problem
For a normally operating motor, the air gap between the stator and the rotor should be kept in a relatively uniform and stable state. However, when there is a virtual or real friction problem between the stator and the rotor for some reason (such as bearing system problems, debris problems), that is, what we call sweeping, at this time, the friction parts will generate heat, causing the temperature of the motor winding to rise from a local to an overall rise. In severe cases, winding to ground or inter-turn faults may occur.

5. The motor operation is not conducive to heat dissipation
In cases, the supporting equipment will meet the necessary heat dissipation environment when the motor is running. However, sometimes the motor may be in an airtight environment, or the environment is too small, and the heat emitted by the motor cannot be exchanged. Naturally, this also increases the temperature rise of the motor.

6. Influence of temperature rise of non-standard casting motors
For small and medium-sized motors, the heat dissipation ribs on the base and end cover meet the requirements. In order to save costs, some manufacturers will reduce the number or size of the heat dissipation ribs, resulting in a reduction in the heat dissipation area of ​​the motor, which is also an unavoidable problem.

Regarding the temperature rise of the motor, including other problems, it is very important to determine the root cause of the problem. In the production, manufacturing and use processes, we must strictly follow the drawings, standards, and processes to prevent unnecessary problems from occurring.