Applications of Motor Thermal Protector in Motor Industry

As one of the leading companies of thermal protectors, Saftty was honored to participate in the Coiltech show in Italy in 2018 and 2019. The company presented the motor thermal protectors and their applications in the electric motor industry. 


About Coiltech show

Coiltech show is an annual exhibition of the coil and electric motor products held in Italy. The worldwide show attracts companies, exhibitors, and visitors from the electric motor industry since the latest developments or new solutions will be shown there.

Saftty was among the companies that impressed the visitors and customers the most because it offers customers all series innovative satisfied motor thermal protectors in high quality.

The necessity of using motor thermal protector in motors

Motors play an important role in electrical equipment, while electric motor thermal protection is significant in motors. Under the surrounding of fast development of science and technology, the motor thermal protectors will replace the overheat switch step by step, mainly for these two reasons:

1.The motor is easier to be broken than before. Due to the continuous development of insulation technology, the motor is required to increase horsepower while reducing its size, so the load of the new motor becomes weaker. In addition, the applications of motors are wider, and the use environment becomes worse, such as in the wet or high temperatures.

2.The performance of the traditional electrical motor is not so good due to its protection devices are overheating switches. The overheat switches are not so sensitive and durable as the thermal protectors, and a new motor thermal protector can provide optimal protection for challenging motors today.

How the motor thermal protector protects the motor

Due to improper use and lack of protection, the motors are easily burned out from time to time. Motor thermal protectors protect the motor in several ways, listed below.

Overvoltage protection

The over-voltage protection is a feature that works to shut down the power supply to the motor when the voltage goes above a preset level. By providing this kind of protection, the motor thermal protector acts immediately to keep the motor intact.

Phase-failure protection

Phase failure is not an uncommon problem, and it affects three-phase motors; it happens when a phase that supplies the motor is disconnected, but the remaining ones continue to function. The consequences of phase failure include decreased engine operation speed, significant loss of motor power, and overload. The thermal protector switch helps avoid this problem.

Current unbalance protection

The motor thermal protector also protects against current unbalance. Current unbalance is the maximum deviation of any current phase from the average current and is divided by the average current. It makes the motor heat up and decreases its efficiency. 

Overheat protection

The unbalanced input three-phase electricity or the long motor working time may cause the motor to overheat. It will reduce the motor’s efficiency and increase the risk of malfunctioning and other problems. As a result, the motor thermal protector works to keep overheating away.

The benefits of using a motor thermal protector

Using thermal motor protection to protect motors is important to save energy, improve production efficiency and economics and ensure safe production.

  • Safety

The main purpose of a motor thermal protector is to halt the temperature climb before it reaches and burns up the motor. Once the electric motor cools down to a safe operating temperature, the motor thermal protector restarts itself. That way, these small devices prevent potentially dangerous scenarios like fires and keep people safe.

  • Cost-effective

The motor thermal protector is a cost-effective solution. By preventing fires and other problems, a motor thermal protector helps you save money you’d spend on repairs or buying new appliances, motors, among other things. 

Motor thermal protectors are an essential part of a quality motor. Saftty commits to offering motor manufacturers more innovative motor thermal protectors with excellent performances. The ST01 series is such a star series also became a hit in the Coiltech show.

Saftty ST01 series product features

Saftty’s motor thermal protector ST01 series is the first China-made round-shaped thermal protector with TUV, UL, and CQC certifications and broke 30 years’ monopoly of German protectors.

It has well sealed, which can prevent product failure from the vacuum impregnation process. Thanks to its compact size, ST01 is suitable to be embedded inside the coil and electric motors. 

With silver-nickel alloy contact and metal case, ST01 has excellent over-current capability and thermal conduction, protecting the electric motors from overvoltage and unbalanced current. 


The motor thermal protector has numerous applications and benefits. Saftty Electronic Technology specializes in R&D and distributes all kinds of thermal protectors in the electrical motor industry and coil, winding, electric heating appliances, and so on. Since 2008, we have kept innovating by setting up test laboratories to provide total overheating and over-current protection solutions to customers. Stable quality, fast lead time, customized service, Saftty is your best choice of thermal protectors.


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