F&F MST-03 Manual

MST-03
Inrush current limiter for
230 V AC circuits
Do not dispose of this device in the trash along with other waste!
According to the Law on Waste, electro coming from households free of charge and can
give any amount to up to that end point of collec� on, as well as to store the occasion of
the purchase of new equipment (in accordance with the principle of old-for-new, regard-
less of brand). Electro thrown in the trash or abandoned in nature, pose a threat to the
environment and human health.

Purpose

MST-03 is designed to limit current overcurrents occurring when
switching on the power supply of circuits with inductive or capa-
citive characteristics (such as LED lighting, pulse power supplies,
lighting fixtures) or non-linear characteristics (such as incande-
scent and halogen lamps).

Functioning

When switched on by a momentary (bell) switch, the initial cu-
rrent flowing through capacitive, inductive or non-linear loads
may exceed the rated values many times. The duration of such
overcurrent is very short (usually less than 0.1 second), but due
to the level of overcurrent it can lead to tripping of overcurrent
protections or bonding of relay contacts in home automation sys-
tems. When switched on, the MST-03 forces the current to flow
through the built-in NTC thermistor limiting the maximum cur-
rent amplitude. After a period of 1÷1.5 seconds the thermistor is
blocked and from then on the current flows into the load witho-
ut any restriction. The resistance of the thermistor depends on
F&F Filipowski sp. j.
Konstantynowska 79/81, 95-200 Pabianice, POLAND
phone/fax (+48 42) 215 23 83 / (+48 42) 227 09 71
www.fif.com.pl; e-mail: biuro@fif.com.pl
- 1 -