Voltage monitoring relay, Exta Free 230V 16A

The automatic phase switch APM-20 is

designed to ensure uninterrupted power

supply of a one-phase receiver in case

of phase loss or RMS voltage value decrease below the norm. The main advantage of the device is a small relative

voltage measurement error, which does

not exceed 1% even for highly distorted

waves. The above is a result of an implementation of the True RMS converter.

The APM-20 device is supplied by three

phases L1, L2, L3 with the L1 phase as

the prior one. The voltage switch threshold (180 V AC), switching time (150

ms) and voltage hysteresis (10 V AC)

have default settings and cannot be

changed by a user. Each phase parameters are optically signalled by means of

LEDs on the front panel of the device.

The internal system of output contacts

assures an increased resistance to their

bonding and protects against phase-to--phase short circuit. The maximum output capacity should not exceed 16 A for

AC1 class receivers. APM-20 is mounted

in distribution boards (TH35 rail). The casing has the width of 2 modules