7235-1-7 Overload Sensing Control

Klixon 7235 and 7236 overload sensing controls are designed for the remote sensing of overloads in aircraft electrical systems or other applicable remote systems. They are for the protection of 28 VDC circuits or for 120 VAC single-phase or three-phase circuits operating at 60 to 1000 Hz. For three-phase AC circuit protection, a 28 VDC control circuit is required. One three-phase relay or three single-phase relays with their coils wired in series may be used in the control circuit. With either arrangement, all three phases will trip open simultaneously when an overload exists in any one phase. Klixon overload sensing controls consist of a bi-metal thermal actuating disc in series with the load terminals and an auxiliary single-phase, double-throw switch fitted to the main base forming a compact vibration-proof construction. The aircraft relay is wired in series with the sensing control through the S2 terminal of the auxiliary switch. When the control senses an overload, the Klixon disc operates the auxiliary switch, breaking circuit S1-S2 and making circuit S1-S3. This opens the relay, thus opening the load circuit.