How to Choose Thermal Overload Switches for Toroidal Transformers?

The thermal overload switch is a device that is designed to cut off the power supply to equipment if the temperature within it reaches a certain level. This can help prevent fires and other damage caused by overheating. The most common thermal overload switch is a bimetallic strip that expands when heated, causing an internal mechanism to close the circuit and turn off the power supply.


The thermal overload switches are primarily used in toroidal transformers but can also be used on other types of electrical equipment as well. In this article, we are going to give you some tips for choosing the best thermal overload switch for toroidal transformers.

Which Thermal Overload Switches Are a Suitable Choice for Toroidal Transformers?

Over-heat is a common issue in toroidal transformers, especially when they are located under load. It can lead to costly damage to the equipment, which is why thermal overload switches are necessary for every toroidal transformer.


Thermal overload switches have a fast response time. This means they can respond quickly to changes in temperature, which makes them ideal for use with high-power applications like toroidal transformers. Here’s how to choose good-quality thermal overload switches for toroidal transformers.

  • Strong Overcurrent Capacity

The first factor is that thermal overload switches should have a strong overcurrent capacity to withstand high currents without failing. Toroidal transformers handle a lot of currents, so it’s important to make sure that the switch has enough power to handle the load and not burn out.

  • Accurate Temperature Control

The second factor is that thermal overload switches should have precise temperature control. Toroidal transformers often need to be controlled at very specific heat levels or temperatures. So, it’s important that the switch can keep track of these levels accurately.

  • High Compressive Strength

Finally, thermal overload switches should have high compressive strength. This means they can withstand heavy loads without breaking or bending under pressure. Because many of these switches are placed in very high-stress situations, it’s important that they can handle the pressure.


Recommend ST01 & ST06 for Toroidal Transformers

ST01 & ST06 are the two most popular thermal overload switches from Saftty designed to protect transformers from overheating and other types of overloads while they’re in operation. They offer excellent reliability, compact size, and easy installation.


They are designed to shut off power when the temperature rises above a set threshold, which will prevent damage to the transformer. They have a rated open temperature of 60℃~180℃ and reset temperature of 35℃~150℃ and 35℃~110℃, respectively, making them suitable for use in industrial and commercial applications.


The ST01 has a rated current of DC24V-10A, DC12V-10A, AC125V-8A, and AC250V-5A, while ST06 has a rated current of AC250V 10A. The ST01 has five models, while the ST06 has three models that are designed to meet the needs of different applications.

The ST01 & ST06 thermal overload sensors offer high accuracy and precision temperature control. They are also widely used in industrial applications where their small size allows them to be installed without affecting the performance of the transformer being protected.


There is no current-based thermal effect, which can cause problems with sensitive transformers. These electric motor thermal overload switches have high compressive strength, which allows them to withstand higher stress levels than other switches. They have been tested and proven in many applications, including electric motors, transformers, and coils.


They’re also incredibly affordable, which makes them great value for money. If you’re looking for a way to protect your equipment from overload, then these thermal overload switches should definitely be on your list!

Saftty: Your Best Choice for Thermal Overload Switches

Saftty is a leading manufacturer of Thermal Switch Protection and has a wide range of products which applied in various industries. We have a strong R&D team that is responsible for the development of new products and improvement of existing products.


Saftty has been providing the highest quality products and services for almost 15 years. We have a large variety of sensors and thermal protectors that can be used to monitor the temperature, humidity, or flow rate. The products are designed with advanced technology and tested by professional engineers.


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