ERMEC: Limitor, temperature switch, fuses distribution

Area of application:
The temperature detector P is used wherever protection against overtemperatures is required. Specific applications include: protection of primary windings in transformers, winding protection in small electric motors, and general temperature protection of small electric equipments.

Function:
The temperature detector P operates independent from any current supply. Temperature detection is effected by means of a bimetal disk which was first dimensioned in accordance with the required cut-off temperature TA. When this fixed cut-off temperature TA is reached, this bimetal disk will snaps over, breaking a contact system and thereby interrupting the electric circuit of the device to be protected. After cooling down and reaching the cut-in temperature TE, the bimetal disk will automatically return into its original position and thus re-make the contact. The electric circuit is closed again.

temperature limiter (latching/self-holding)

Area of application:
The temperature limiter Q is used wherever, on the one hand, protection against overtemperatures is required, and, on the other hand, automatic cut-in of the device to be protected - subsequent to a follow-on cooling down period - is undesirable or not permissible.

Function:
The temperature limiter Q operates independent from any current supply. Temperature detection is effected by means of a bimetal disk which was first dimensioned in accordance with the required cut-off temperature. When this fixed cut-off temperature TA is reached, this bimetal disk will snap over, breaking a contact system and thereby interrupting the electric circuit of the device to be protected. In order to prevent any automatic cut-in of the circuit when the switch cools down again, the switch is equipped with an electric latch/self-holding device.

latch / self-holding device:
By means of a resistor heat is generated by the supply voltage applied after breaking the contact. This heat prevents any decrease in temperature below the value necessary for the cut-in temperature TE. In this was, the switch will keep its contact open, irrespective of its ambient temperature. Cut-in of the switch, and thus closing the circuit, will be possible only after disconnection from the supply voltage.

current and temperature limiter

Area of application:
The current and temperature limiter Y is used wherever, on the one hand, protection against overtemperatures as well as against overcurrents is required, and, on the other hand, automatic cut-in of the device to be protected - subsequent to a follow-on cooling down period - is undesirable or not permissible.

Function:
The current and temperature limiter Y operates dependent on any current supply. Temperature detection is effected by means of a bimetal disk which was first dimensioned in accordance with the required cut-ouf temperature. When this fixed cut-off temperature TA is reahced, this bimetal disk will snap over, breaking a contact system and therby interrupting the electric circuit of the device to be protected.

Current sensitivity:
In the case of an obvious current increase (blocking current or short-circuit current) a resistor, lying in series with the contact system inside the limiter, heats the bimetal disk to its cut-off temperature TA very quickly. When this cut-off temperature TA is reached, the bimetal disk will snap suddenly and break the contacts of the switch. In order to achieve an optimum adaptation to the specific current value the resistor values are graded.

self-holding:
By means of a resistor heat is generated by the supply voltage applied after breaking the contact. This heat prevents any decrease in temperature below the value necessary for the cut-in temperature TE. In this was, the switch will keep its contact open, irrespective of its ambient temperature. Cut-in of the switch, and thus closing the circuit, will be possible only after disconnection from the supply voltage.

temperature / thermo switch

	The thermo switch operates independent from any current supply. The thermal operation system works by means of bimetal snap disks separated from the contact system galvanically. The housing, the covering cap and the fastening are dead circuit.
Thermo switches only react when external thermal heating affects them. The thermal coupling to the source of heat is effected by means of a bimetal disk lying directly below the metallic covering cap.
	Due to small size, high reliability, independence of location and the fact that it is totally maintenance-free, a thermo switch is the ideal instrument for perfect thermal protection.

Types of contacts/contact types:

KO - break contact which will automatically return into its original position.
KS - make contact which will automatically return into its original position.
KB - limiter with mechanical latch/self-holding
SB - break contact with electric latch/self-holding

FUSES

If someone says of somebody else "he blew a fuse", then you can usually expect the worst. This is an example of how everyday expressions do not always reflect accurately the electronic definition, because fuses that blow fulfill their purpose and cut off the power supply. And this is exactly what Limitor thermal fuses do. In contrast to our detectors, limiters and thermostats, these components are designed as one-shot fuses.