Application notes

N°104

"SMART" CONTACTORS

SMART CONTACTORS are hybrid devices combining standard production power relays with an electronic module and

electrical sensor. Their primary purpose is to control the flow of power to equipment without the use of the conventional circuit

breaker panel. They are controlled by and provide information to a logic network or host computer.

The functions and requirements of "SMART CONTACTORS" will vary, depending on the power distribution or control system

involved. Leach International provides "SMART" capability from 25 amperes to 305 amperes, single and three phase AC, and

up to 1000 amperes DC.

In addition to I²t curves, devices can be configured to respond to current, voltage or power. The standard operating

temperature range is -55°C to +71°C, and weights will vary in junction of the application.

The photos below show two current applications:

Fig. 1. Used in APU start circuit on board commercial aircraft.

Fig. 2. Used in three phase secondary bus distribution onboard military fighter aircraft.

Figure 1

Figure 2

Date of issue: 6/00

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