STW20K
12440-0702-03
Page
3 / 8
www.ziehl.de
1
General Notes
Compliance with the following instructions is mandatory to ensure the functionality and safety of the
product. If the following instructions given especially but not limited for general safety, transport,
storage, mounting, operating conditions, commissioning and disposal / recycling are not observed,
the product may not operate safely and may cause a hazard to the life and limb of users and third
parties.
Deviations from the following requirements may therefore lead both to the loss of the statutory
material defect liability rights and to the liability of the buyer for the product that has become unsafe
due to the deviation from the specifications.
2
Display and controls
1. LED green Power On
2. LED red Alarm
3
Application and short description
The current relay STW20K monitors the current in up to 3 lines with current transformers STWA1 (AND
circuit). If there is a current in all 3 monitored lines, the relay (2 change-over contacts) picks up. If there is no
current in at least one of the lines, the relay releases. The relay works in closed circuit current. When voltage
is applied to the STW, the relay signals an alarm until the it has picked up.
Identifies power failure with 1- or 3-phase electrical consumers, e.g. with monitoring of heating elements or
heating installations where a constant heating has to be guaranteed.
A further application is the identification of phase failure, monitoring of fuses, or triggering of operating hours
counters.
If the switching threshold is not reached due to low currents of less than 1 A, the monitored wire should be led
multiple times through the transformer STWA1, STWA1H. Not required inputs have to be connected to a
occupied input.
4
Overview of functions
•
3 current transformers STWA1
•
AND-evaluation
•
relay output 2 CO
•
Switching point approx. AC 1 A
•
LED-display for power on and alarm
•
housing design K
