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.
