18AM-B series thermal overload relay works as an overcurrent protection device mainly in single-phase AC motor (50Hz, 220V). It helps to prevent the motor from burning out in some non-normal operating states like overload and stalling.

This kind of thermal protector is equipped with bimetal of certain shape, which is a principle temperature sensing component to change the state of the contacts and cut off the circuit. With the features of small volume and high sensitivity, 18AM-B series thermal circuit breaker is mainly applied in battery, air conditioner motor, and automotive seat heating system, etc.

Generally, in an electrical circuit controlled by thermal overload relay, when the temperature rises to the limit, the bimetal will force the 2 contacts to separate, and switch off the circuit. When the temperature drops to the prescribed range, the contacts will touch and the circuit is closed.

Difference between 18AM-B and 18AM-C
18AM-B and 18AM-C series are collectively called 18AM series. They share the similar property, performance, and internal structure. The difference is in the casing. The casing of 18AM-B thermal switch is made from stainless steel (used in conjunction with insulating sleeve), and 18AM-C protector adopts insulated plastic enclosure.

Main Features
1. The reinforced stainless steel enclosure allows the thermal protector to be able to bear 30MPa of pressure. Its wall thickness is no less than 0.5mm. For application in plastic motor, the thermal protection device should be mounted inner the motor structure
2. The max capacity of contacts: AC 250V/8A (6000 times of service); AC 125V/12A (6000 times of service)
3. Opening temperature: 50-130℃, in increment of 5℃; tolerance of opening temperature: ±5℃
4. Standard wires: UL3135 #20, red, 70mm; wire length and length of stripping is customizable

Open and Close Temperature

Index
Induction Motor Thermal Switch, Bimetal Snap Action Thermal Protector
Battery Protector, Vehicle Motor Thermal Protector
Air Conditioner Motor Thermal Protector