Current-Relay STW20K

Current Relay for AC-Detection, AND-Evaluation, 3 Transformers, Housing type K for switch-gear cabinet mount

Share: Facebook   WhatsAppWhatsApp   E-Mail

Part number

AC/DC 24 - 240 V

Product 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. Not required inputs have to be connected to a occupied input.


  • 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

Technical Data

Power supply Us


AC/DC 24 - 240 V, 0/50/60 Hz, < 1 W, < 4 VA
(DC 20 - 297 V, AC 20 - 264 V)


Output relay


2 CO


Type of contact


type 2 see general technical informations




3 channel/AND


Transformer input


1 to 3, type STWA 1


Overload cap.continous/max 10s


100 A / 300 A


Switching point on


≤ AC 1 A


Switching point off


≥ AC 0,3 A




± 20%


Switch-off delay


approx. 0,3 s


Switch-on delay


approx. 0,3 s


Testing conditions


see general technical informations


rated ambient temperature range




Dimensions H x B x T


Design K: 75 x 22,5 x 110 [mm], 12-pol


Protection housing / terminals


IP 30 / IP 20




approx. 120 g




Operating manual

Operating Manual (french)