With the development of the technology, the scope of the electric motor is becoming more and more widely used, especially the use of the electric motor in the daily life and production is also becoming more and more important. Electric motor is an indispensable part in many applications, but all kinds of motor burning accidents also occur frequently, causing many unnecessary losses and dangers
In practice, the motor burning has the following reasons
The main feature of the motor burning is heating, and the main reason for the motor burning is that the stator winding heating, heating and cooling of the motor is a very slow change process, therefore, the motor embedded thermal protector can achieve effective protection effect
Sometimes the motor will be blocked, after blocking the motor current will far exceed the rated current, so that the motor overload and burn out. Therefore, it is necessary to protect the motor overload reverse time characteristic, generally by the overcurrent relay or thermal relay
Most of the damage to the motor is caused by phase deficiency. The motor burning fault caused by phase deficiency accounts for 80% of the total motor burning fault. For a long time, there is a general view that the phase absence operation will lead to the motor winding overheating and damage, and that the thermal protector temperature rise is the most direct and effective phase absence protection method, but the reality is that if the motor lacks phase operation, it will burn down in a very short time. Relying on the conventional antitime limit characteristic cannot protect the phase of the motor
The role of the motor thermal protector is to carry out a comprehensive protection control for the overcurrent heat overload of the motor, in the motor appears overcurrent, undercurrent, phase breaking, plugging, short circuit, overvoltage, under voltage, leakage, three-phase imbalance, overheating, grounding, bearing wear, fixed rotor eccentric, winding aging alarm or protection control.
How does the thermal protector protect the motor? Thermal protector, also known as temperature switch, temperature control switch, etc. Is a kind of double metal sheet as a temperature sensor of temperature switch, electrical normal work, double metal sheet in a free state, contact in closed / open state, when the temperature rises to action temperature value, the double metal element heat produce internal stress and rapid action, open / close the contact, cut off / on circuit, thus play a thermal protection role.HKW Electronics' 9700 and 17AM series thermal protectors are the first pure temperature type temperature switch with dual UL and TUV certification certification in China. When the circuit is connected, the current does not pass through the double sheet, there is no current thermal effect, and the temperature control is more accurate.
Connection mode of thermal protector and motor: three-phase motor star wiring
Because many motor manufacturers use vacuum immersion paint production process to ensure the coil insulation. Ann electronics after repeatedly improving the process and the purchase of efficient vacuum equipment, the production of thermal protector to achieve extremely high sealing, can prevent the vacuum extraction process of product failure. The loss efficiency of vacuum immersion paint is reduced to less than one thousandth, becoming the lowest defect rate in the industry
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