Current-Relay type STW20K

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Article number: S225121

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.

Applications

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.

Features

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

Product group:	Mains Monitoring
Input/ Measured parameter:	Current detection yes/no
Outputs:	Outputs/Relays
Supply voltage:	AC/DC 24-240 V
Design:	Mount in switchgear cabinet
Applications:	Protection of motors

Technical specifications

CAD Data

Certificates

CE Decl. of conformity

FAQ / Product videos

Accessories

Current Transformer Type STWA1

The STWA1 current transformer is made to match the STW current monitor. One current transformer is required for each line being monitored. The STWA1 consists of a climate-proven sealed-in coil with toroidal tape core. The connection cables are permanently fixed to the transformer and are 1 m in length. The level of the current to be monitored is limited to 100 A continously, 300 A for max. 10s.In case of current of more than approx. 5 A, an LED can be triggered directly via the STWA 1 current transformer. Thus it's easy for users to visually monitor the current conduction in a line. The LED is protected by an anti-parallel diode or by its connection in series. A protective resistor is necessary depending on the LED used or the level of current being monitored.Weight: approx. 43 g

Current-Sensor Type S1

Recording of welding currents (mounting at ground wire) for controlling dedusting plants in combination with ZIEHL-controls type STW. Recording the state of a consumer of electricity (on or off or defective).In general the current-sensor S1 is used where the current-flow is to be detected, with the exact value of the current either known from the power consumption of the connected consumer or does not matter for the evaluation.For evaluation of measuring data in more than 1 cable, these outputs of several current-sensors can be connected in parallel (OR-evaluation).switching point app. 5 A (option: adjustable 5-30 A)monitoring of AC and DC currentsLED for current flowmounting without disconnection of cable possible2 transistor-outputs, switching + and -, direct connection to a PLC possibleconnection to current-relays ZIEHL type STWrobust, sealed executionoverload capacity: unlimited

Alternative

Current-Relay type STW20V

The current relay STW20V monitors the current in up to 3 lines with current transformers STWA 1 (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. This can be avoided if the device is constantly alive and monitoring is started by closing a contact at the Enable input. With a bridge at the Enable input, monitoring is automatically started when voltage is applied.3 inputs (transformer STWA1)3 x current-sensor S1 (powersupply required)AND-evaluationoutput relay 2 COswitching point app. AC 1 AEnable-inputstorage of alarms or Auto-ResetLEDs power on and alarm housing V4 for mounting on DIN-rail or wall-mountApplicationsIdentifies 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.