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1SVR730120R3300 ABB CT-ARS.21S Timer True OFF-Delay 2C/O
ABB CT-ARS.21S electronic true OFF-delay time relay with 7 time ranges from 0.05 s to 10 min, 24–240 V AC/DC supply and two changeover relay contacts.
£98.26
Why Choose the ABB CT-ARS.21S True OFF-Delay Timer?
The ABB CT-ARS.21S is a single-function electronic time relay from the ABB CT-S timer range, designed to provide reliable true OFF-delay timing for industrial automation and electrical control systems. It provides a true delay-on-break function without requiring an auxiliary voltage, allowing the relay outputs to remain energised for a defined period after the control signal is removed.
The CT-ARS.21S provides 7 selectable time ranges from 0.05 s to 10 min and operates from a universal 24–240 V AC/DC control supply. Front-face adjustment allows the required delay to be configured for machinery, control panels and automated processes.
The timer features 2 c/o (SPDT) relay contacts rated at 250 V / 4 A. Its compact 22.5 mm wide housing uses screw connection technology with double-chamber cage terminals and is suitable for DIN rail installation in industrial control cabinets.
Key Advantages
- Reliable true OFF-delay electronic time relay for industrial automation.
- True delay-on-break operation without auxiliary voltage.
- 7 selectable time ranges from 0.05 s to 10 min.
- Universal 24–240 V AC/DC control supply.
- 2 c/o (SPDT) relay contacts for flexible switching.
- 250 V / 4 A rated output contacts.
- Compact 22.5 mm wide DIN rail housing.
- Screw connection technology with double-chamber cage terminals.
- Front-face adjustment for straightforward time selection.
- Sealable transparent cover available as an accessory to help prevent unauthorised adjustments.
Key Features
- ABB CT-S timer range.
- True OFF-delay (delay-on-break) timing function.
- Operation without auxiliary voltage.
- 7 selectable time ranges from 0.05 s to 10 min.
- 24–240 V AC/DC rated control supply.
- 2 c/o (SPDT) contacts.
- 250 V / 4 A rated output contacts.
- 50/60 Hz AC or DC operation.
- Screw connection technology with double-chamber cage connection terminals.
- DIN rail mounting for compact control cabinet installation.
- LED status indication.
- Sealable transparent cover available as an accessory.
Reliable True OFF-Delay Timing for Industrial Automation
The ABB CT-ARS.21S provides true OFF-delay timing for applications where relay outputs need to remain active for a defined period after the control signal is removed. Because the timing function operates without an auxiliary voltage, it provides a practical solution for delayed switch-off applications in industrial control systems.
With seven selectable time ranges covering 0.05 s to 10 min, the CT-ARS.21S is suited to short machine-control delays, sequencing operations and other timed switching requirements. Its two changeover relay contacts provide flexible interfacing with contactors, signalling circuits, machinery and other industrial control equipment.
Typical Applications
- Industrial automation and control panels.
- Motor and contactor control circuits.
- Machine sequencing and timed control.
- Conveyor and production machinery control.
- Delayed switch-off applications.
- Process automation and equipment sequencing.
- Industrial signalling and alarm circuits.
- Cooling and ventilation run-on control.
- Lighting and timed shutdown circuits.
- Control systems requiring true OFF-delay operation without auxiliary voltage.
Technical Specifications
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| Contacts | 2 C/O | |
|---|---|---|
| Mounting Type | DIN rail | |
| Device Type | Single-function timer | |
| Timing Function | Off-delay | |
| Timing Range | 0.05 s – 10 min | |
| Switching Current (A) | 4 A | |
| Series | CT-S Time Relays | |
| Product type | Electronic time relay | |
| Timer relay type | True OFF-delay | |
| Timing function | True OFF-delay (delay-on-break) | |
| Auxiliary voltage | Not required | |
| Time range | 0.05 s–10 min | |
| Number of time ranges | 7 | |
| Control supply voltage | 24–240 V AC/DC | |
| Output | 2 c/o (SPDT) contacts | |
| Rated operational voltage | 250 V | |
| Rated operational current | 4 A | |
| Rated frequency | 50 / 60 Hz / DC | |
| Rated insulation voltage | 500 V input circuit / output circuit, 300 V between output circuits | |
| Maximum operating voltage UL/CSA | 300 V AC output circuit | |
| Protection rating | IP50 | |
| Operating temperature | -25–+60 °C | |
| Storage temperature | -40–+85 °C | |
| Mounting type | DIN rail mounting | |
| Terminal type | Screw terminals, double-chamber cage connection | |
| Housing width | 22.5 mm | |
| Dimensions (W × H × D) | 22.5 × 85.6 × 103.7 mm | |
| Net weight | 0.124 kg | |
| Housing material | UL 94 V-0 |
Frequently Asked Questions
What is the ABB CT-ARS.21S used for?
The CT-ARS.21S is an electronic true OFF-delay time relay used to keep control outputs active for a defined period after the control signal is removed in industrial automation and control systems.
What timing function does the CT-ARS.21S provide?
The CT-ARS.21S provides a true OFF-delay (delay-on-break) timing function without requiring an auxiliary voltage.
What time range does the CT-ARS.21S provide?
The CT-ARS.21S provides 7 selectable time ranges covering 0.05 s to 10 min.
What control supply voltage does the CT-ARS.21S require?
The CT-ARS.21S operates from a universal rated control supply of 24–240 V AC/DC.
How many outputs does the CT-ARS.21S have?
The CT-ARS.21S has two changeover (2 c/o) SPDT relay contacts, rated at 250 V / 4 A.
Trusted by Automation Engineers Worldwide
ABB CT-S true OFF-delay time relays provide dependable timed switching for industrial automation systems where controlled delay-on-break operation, universal AC/DC supply compatibility and compact DIN rail installation are required.
