Governor / AVR Interfacting Note

SELCO A/S · Betonvej 10 · DK-4000 Roskilde · Pho: +45 70 26 11 22 · http://www.selco.com

Leroy Somer - R448

Principle of operation

The Leroy Somer R448 voltage regulator can be externally controlled by a 1 kOhm potentiometer at

the terminals ST4 (the bridge which normally shorts the terminals at ST4 must first be removed).

By turning the potentiometer it is possible to obtain a voltage regulation of +/-10 % according to the

nominal voltage. Alternativly the R448 can be controlled using a -1 to +1 VDC signal instead of the

potentiometer.

External speed control by DC voltage

Configure DC voltage output to -1 to +1 VDC.

DC voltage signal to R448 ST4 upper terminal

DC voltage reference to R448 ST4 lower terminal

External speed control by Potentiometer

Potentiometer: 1 kOhm / 5 turn (or 10 turn for slower operation)

Increase speed relay (e.g. T4500 terminal 14) to E7800 terminal 1

Decrease speed relay (e.g. T4500 terminal 16) to E7800 terminal 3

Control Voltage positive to source terminal of relays (e.g. T4500 terminal 15).

Control Voltage negative to E7800 terminal 2

E7800 terminal 4 to R448 ST4 lower terminal (zero ohms)

E7800 terminal 5 to R448 ST4 upper terminal (Wiper)

E7800 terminal 6 to R448 ST4 upper terminal (full resistance)