Thermal Overload Relays

ATO as a Chinese supplier provides JR28 and JR36 two series 3 phase thermal overload relays. 25A, 32A, 36A, 63A, 93A, 160A rated current can be chosen.
The thermal overload relays have a rugged, flame-retardant case design to withstand abrasion and high temperatures. Thermal overload relays can be manufactured wholesale and our company can provide you with customized services.

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Thermal Overload Relays

Thermal overload relay is used for overload protection of motor or other electrical equipment and electrical lines. As a type of overload protection component, thermal relay has wide applications in production due to its small size, simple structure, and low price.

ATO supplier in China manufactures JR28 and JR36 two series 3 phase thermal overload relays. 25A, 32A, 36A, 63A, 93A, 160A rated current can be chosen. The 3-phase thermal overload relay is equipped with a flame retardant shell to withstand wear and high temperature. Three-phase thermal relay is often used in AC motors.

JR28 3 Phase Thermal Overload Relay

JR28 3 phase thermal overload relay rated operating current is available at 25A, 36A and 93A. Ambient air temperature between -5 ℃ and 40 ℃.

JR26 3 Phase Thermal Overload Relay

ATO thermal overload relay features overcurrent and phase-failure protection functions. Optional current 20, 63, 120 Amps, rated insulation voltage 690V.

Strong Adaptability

Thermal overload relays made by ATO in China, can work in different environments, such as high temperature, low temperature, humidity, dust and other environments, and can meet the needs of various industrial production.

At the same time, it can also be adapted to the same type of loads, such as AC motors, DC motors, control circuits and other systems.When selecting and using thermal overload relays, they can be selected and configured according to specific application scenarios and needs.

High Reliability

Thermal Overload Relay in Overload Protection

Thermal overload relay is mainly used for circuit overload protection. Its working principle is that after overloading the current overheating element, the bimetallic sheet is heated and bent to push the action mechanism to drive the contact action, so that the circuit is disconnected to realize load stopping and play the role of overload protection.

In view of the fact that the heat transfer takes a long time during the thermal bending process of the bimetallic sheet, the thermal relay cannot be used as short circuit protection, but only as overload protection.

Thermal Overload Relay Functions

In modern industrial automation activities, most of the power sources come from motors. The rotational force provided by the motor drives belts, gears, chains, etc., so it becomes the absolute core part. No one will ignore the protection of the core driving force. (Industrial lenses, robots, milling machines)

Thermal relays are used for motor overload protection, phase failure protection, current unbalanced operation protection, and control of the heating status of other electrical equipment. A protective appliance that uses the thermal effect of current to push the action mechanism to close or break the contact system.

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Thermal Overload Relays Material

Silver alloy contact

Silver alloy contacts can improve electrical conductivity, making them stronger, more sensitive, and more load-bearing.

Copper pin

The design of all-copper pins has the characteristics of good electrical conductivity and more stable operation.

Copper contact plate

The copper contact plate makes the relay have good current conductivity and enhances the smooth operation.

Thermal Overload Relay FAQ

How does thermal overload relay work?

A thermal overload relay is a protective device used in electrical circuits to prevent overheating of motors or other equipment. It works by monitoring the current passing through the circuit. When the current exceeds a preset threshold for an extended period, typically due to a fault or excessive load, the relay's internal bimetallic strip or thermal element heats up. This causes the relay to trip, opening the circuit and disconnecting power to the equipment. The bimetallic strip's differential expansion due to temperature change is what triggers the relay's action, providing an effective safeguard against overheating and potential damage to the equipment.

Can thermal overload relay be reset manually?

Yes, a thermal overload relay can typically be manually reset. It is a protective device used in electrical circuits to prevent overheating of motors and other equipment. When it detects excessive heat, it trips and disconnects the power supply to the equipment. Once the thermal overload condition is resolved and the relay cools down, it can be manually reset by pressing a reset button or lever on the relay. This action restores power to the equipment, allowing it to operate again. Manual reset ensures that the issue causing overheating is addressed before the equipment is allowed to function, enhancing safety and preventing damage.

Can thermal overload relay be used in hazardous environments?

Thermal overload relays are not typically recommended for use in hazardous environments, especially those with explosive or flammable materials. These relays are primarily designed for motor protection by detecting overheating due to excessive current flow. In hazardous environments, specialized equipment like explosion-proof or intrinsically safe devices should be used to ensure safety. These specialized devices are engineered to prevent electrical sparks or arcs that could ignite flammable gases or dust. It's crucial to adhere to local safety regulations and consult with experts to select the appropriate equipment for hazardous environments to minimize the risk of ignition and ensure worker safety.

How does a thermal overload relay differ from a circuit breaker?

A thermal overload relay and a circuit breaker are both protective devices used in electrical systems, but they serve different purposes. A thermal overload relay is primarily designed to protect electric motors from overheating due to excessive current. It monitors motor current and trips when it detects prolonged overcurrent conditions, preventing damage to the motor. In contrast, a circuit breaker is a general-purpose protective device that safeguards an entire electrical circuit from overloads, short circuits, and faults. It interrupts the flow of electricity when it senses these issues, ensuring overall circuit safety. The key difference lies in their specific applications and the scope of protection they offer.

Are there any maintenance requirements for thermal overload relay?

Yes, thermal overload relays require periodic maintenance to ensure their proper functioning. This typically involves checking for dust or debris accumulation, cleaning the relay, and inspecting its connections for signs of corrosion or wear. Additionally, it's important to test the relay's trip and reset mechanisms to ensure they operate as designed. Regular calibration and testing are crucial to guarantee the relay's accuracy in protecting motors from overheating. It's advisable to follow the manufacturer's recommendations for maintenance intervals and procedures to keep the thermal overload relay in optimal condition and maintain the safety of motor-driven equipment.

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An electromagnetic relay is an electrical switch that uses an electromagnet to control the flow of current in a circuit. When the electromagnet is energized, it mechanically closes or opens the switch, allowing or interrupting the electrical flow.

Signal Relay

A signal relay is an electromagnetic switch that controls the flow of electrical signals in electronic circuits. It allows a low-power input signal to control a higher-power output signal, enabling the isolation and amplification of electrical signals.

Thermal Overload Relay

A thermal overload relay is an electrical device that protects motors from overheating by monitoring their current and disconnecting power when excessive heat is detected, preventing damage or fires in industrial applications.