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