Residual current device-A type-filter for harmonics-manual or automatic reset
| AUX |
24 Vac |
| OUTPUT |
1 relay with SPDT contact |
| INSERTION |
low-voltage lines with transformer series Del-Dela |
| THRESHOLDS |
30 mA...30 A with electric block t=0 at 30 mA |
| FORMAT |
2 DIN module |
| TYPE |
Residual current device-A type-filter for harmonics-manual or automatic reset |
Product is in quote request list
- Differenzstromrelais - Oberwellenfilter, Typ A
- Rücksetzung manuell (am Gerät oder ferngesteuert) oder automatisch
- Anzeige des momentanen Differenzstromes IΔn in in Prozent mit 4 LED
- Zweidrahtverbindung mit Ringstromwandler Del - DelA, Niederspannungsnetz
- Abmessungen : 2 Modul DIN
- Relais Ausgang : 1 Wechselkontakt (SPDT)
- Hilfsspannung: 24Vac o. 115Vac o. 230Vac o. 240Vac o. 400Vac o. 20...150Vdc/48Vca
- Wählbarer Grenzwert : 30mA...30A - keine Ansprechverzögerung (t=0) bei 30mA
Product is in quote request list
Residual current device-A type-for public lighting systems, traffic lights and equipment unattended-manual or automatic reset-istantaneous value %Idn on 4 led
| AUX |
230 Vac |
| OUTPUT |
2 relays with SPDT contact |
| INSERTION |
low-voltage lines with transformer series Del-Dela |
| THRESHOLDS |
30 mA...30 A with electric block t=0 at 30 mA |
| FORMAT |
4 DIN modules |
| TYPE |
Residual current device-A type-for public lighting systems, traffic lights and equipment unattended-manual or automatic reset-istantaneous value %Idn on 4 led |
Product is in quote request list
Residual current device-A type-filter for harmonics-manual reset-istantaneous value %Idn on 4 led
| AUX |
20...150 Vdc/48 Vac |
| OUTPUT |
1 relay with SPDT contact (alarm) + 1 relay with SPST contact (pre-alarm or power fall) |
| INSERTION |
low-voltage lines with transformer series Del-Dela |
| THRESHOLDS |
30 mA...30 A + pre-alarm 50% with electric block t=0 at 30 mA |
| FORMAT |
4 DIN modules |
| TYPE |
Residual current device-A type-filter for harmonics-manual reset-istantaneous value %Idn on 4 led |
Datasheet
Product is in quote request list
Residual current device-A type-filter for harmonics-manual reset-istantaneous value %Idn on 4 led
| AUX |
400 Vac |
| OUTPUT |
1 relay with SPDT contact (alarm) + 1 relay with SPDT contact (pre-alarm or power fail) |
| INSERTION |
low-voltage lines with transformer series Del-Dela |
| THRESHOLDS |
30 mA...30 A + pre-alarm 50% with electric block t=0 at 30 mA |
| FORMAT |
4 DIN modules |
| TYPE |
Residual current device-A type-filter for harmonics-manual reset-istantaneous value %Idn on 4 led |
Product is in quote request list
Residual current device-A type-filter for harmonics-manual or automatic reset
| AUX |
24 Vac |
| OUTPUT |
1 relay with SPDT contact |
| INSERTION |
low-voltage lines with transformer series Del-Dela |
| THRESHOLDS |
30 mA...30 A with electric block t=0 at 30 mA |
| FORMAT |
48x48 mm |
| TYPE |
Residual current device-A type-filter for harmonics-manual or automatic reset |
Product is in quote request list
Residual current device-A type-filter for harmonics-manual or automatic reset
| AUX |
20...150 Vdc/48 Vac |
| OUTPUT |
1 relay with SPDT contact (alarm) + 1 relay with SPST contact (alarm) |
| INSERTION |
low-voltage lines with transformer series Del-Dela |
| THRESHOLDS |
30 mA...30 A with electric block t=0 at 30 mA |
| FORMAT |
48x48 mm |
| TYPE |
Residual current device-A type-filter for harmonics-manual or automatic reset |
Product is in quote request list
Residual current device-A type-filter for harmonics-manual reset-istantaneous value %Idn on 4 led
| AUX |
24 Vac |
| OUTPUT |
1 relay with SPDT contact (alarm) + 1 relay with SPDT contact (pre-alarm or alarm) |
| INSERTION |
low-voltage lines with transformer series Del-Dela |
| THRESHOLDS |
30 mA...30 A + pre-alarm 50% with electric block t=0 at 30 mA |
| FORMAT |
72x72 mm |
| TYPE |
Residual current device-A type-filter for harmonics-manual reset-istantaneous value %Idn on 4 led |
Product is in quote request list
Residual current device-A type-filter for harmonics-manual or automatic reset-istantaneous value %Idn on 4 led
| AUX |
24 Vac |
| OUTPUT |
1 relay with SPDT contact (alarm) + 1 relay with SPDT contact (pre-alarm) |
| INSERTION |
low-voltage lines with transformer series Del-Dela |
| THRESHOLDS |
30 mA...30 A + pre-alarm 50% with electric block t=0 at 30 mA |
| FORMAT |
72x72 mm |
| TYPE |
Residual current device-A type-filter for harmonics-manual or automatic reset-istantaneous value %Idn on 4 led |
Product is in quote request list
Residual current device-A type-filter for heavy industrial applications-manual reset-istantaneous value %Idn on 4 led
| AUX |
24 Vac |
| OUTPUT |
1 relay with SPDT contact (alarm) + 1 relay with SPDT contact (pre-alarm or alarm) |
| INSERTION |
low-voltage lines with transformer series Del-Dela |
| THRESHOLDS |
50 mA...30 A + pre-alarm 50% |
| FORMAT |
72x72 mm |
| TYPE |
Residual current device-A type-filter for heavy industrial applications-manual reset-istantaneous value %Idn on 4 led |
Product is in quote request list
Residual current device-A type-filter for harmonics-manual reset-istantaneous value Idn on display (3 digit)
| AUX |
24 Vac |
| OUTPUT |
1 relay with SPDT contact (alarm) + 1 relay with SPST contact (pre-alarm or alarm) |
| INSERTION |
low-voltage lines with transformer series Del-Dela |
| THRESHOLDS |
30 mA...30 A + pre-alarm 50% with electric block t=0 at 30 mA |
| FORMAT |
72x72 mm |
| TYPE |
Residual current device-A type-filter for harmonics-manual reset-istantaneous value Idn on display (3 digit) |
Product is in quote request list
Residual current device-A type-filter for harmonics-manual reset-istantaneous value %Idn on 4 led
| AUX |
20...150 Vdc/48 Vac |
| OUTPUT |
1 relay with SPDT contact (alarm) + 1 relay with SPDT contact (pre-alarm or alarm) |
| INSERTION |
low-voltage lines with transformer series Del-Dela |
| THRESHOLDS |
30 mA...30 A + pre-alarm 50% with electric block t=0 at 30 mA |
| FORMAT |
96x96 mm |
| TYPE |
Residual current device-A type-filter for harmonics-manual reset-istantaneous value %Idn on 4 led |
Product is in quote request list
Residual current device-A type-filter for heavy industrial applications-manual reset-istantaneous value %Idn on 4 led
| AUX |
24 Vac |
| OUTPUT |
1 relay with SPDT contact (alarm) + 1 relay with SPDT contact (pre-alarm or alarm) |
| INSERTION |
low-voltage lines with transformer series Del-Dela |
| THRESHOLDS |
50 mA...30 A + pre-alarm 50% |
| FORMAT |
96x96 mm |
| TYPE |
Residual current device-A type-filter for heavy industrial applications-manual reset-istantaneous value %Idn on 4 led |
Product is in quote request list
Closed core ring transformer for Delta residual current device
| CABLE/PASSING BUS BAR |
ø 60 mm |
| CURRENT |
lowest Idn 0,03 A |
| TYPE |
Closed core ring transformer for Delta residual current device |
Product is in quote request list
Toroid suitable for residual current device Delta connected on measuring C.T. /5A
| CURRENT |
150/5 A |
| TYPE |
Toroid suitable for residual current device Delta connected on measuring C.T. /5A |
Product is in quote request list
Open core ring transformer for Delta residual current device
| CABLE/PASSING BUS BAR |
ø 110 mm |
| CURRENT |
lowest Idn 0,5 A |
| TYPE |
Open core ring transformer for Delta residual current device |
Product is in quote request list
Open core ring transformer for Delta residual current device
| CABLE/PASSING BUS BAR |
ø 300 mm |
| CURRENT |
lowest Idn 1 A |
| TYPE |
Open core ring transformer for Delta residual current device |
Product is in quote request list
Residual Current Relay / Toroidal Current Transformer (RCD Monitoring)
A residual current relay – often used together with a toroidal current transformer – monitors electrical circuits for leakage currents (residual currents). The toroidal current transformer measures the vector sum of all conductor currents; if the result is non-zero, the relay detects a leakage current (e.g. earth fault, insulation failure). When a preset threshold is exceeded, the relay triggers an alarm or activates a switch to cut off or alert — providing crucial protection against fault currents.
This combination is widely used in safety systems for switchgear, machines or electrical installations. Devices are typically DIN-rail modules and easy to install or retrofit. They enable reliable detection and fast reaction to leakage currents — reducing risk of electric shock, fire or equipment damage.
Questions & Answers on Residual Current Relays / Toroidal Current Transformers
What is a residual-current relay?
A device that monitors for leakage current in an electrical circuit by using a current transformer to detect imbalance among conductor currents.
How does a toroidal current transformer work?
It encloses all conductors of a circuit; the sum of currents should be zero. If there is an imbalance, the resulting residual current is detected, indicating a fault or leakage.
When does the relay trigger?
When the residual current exceeds a predefined threshold — adjustable depending on the device.
What output does the relay provide?
Typically a switch contact or alarm signal that can be used to cut power, trigger warnings or control external devices.
Where is such a relay used?
In switchgear, control cabinets, building installations, machine controls — wherever earth-fault monitoring or safety assurance is needed.
Is the system suitable for single- and multi-phase networks?
Yes — as long as all conductors of the circuit pass through the toroidal sensor, the system works for single, three or multi-phase installations.
How is it installed?
The toroidal transformer is placed around the cable bundle, and the relay module mounted on a DIN rail and wired accordingly. Installation and retrofitting is typically straightforward.
Why is this combination important?
Because it provides automatic detection of leakage currents or earth faults, improving safety, preventing hazards such as fire or electric shock, and protecting equipment.
Are there any prerequisites or precautions?
All conductors must pass through the toroidal sensor; the transformer must be dimensioned correctly. Regular inspection is recommended to ensure continued proper function. Incorrect installation or missing conductors can render the protection ineffective.
