Off-Delay Time Delay Relays

Off-Delay Time Delay Relays (power-off delay) are industrial timer relays designed to keep an output energised for a preset time after the control signal is removed. They are used to ensure controlled run-down, purge cycles, and delayed release of contactors, improving safety and process stability in control panels and automation.

🔧 Technical Highlights:

• Operating Principle: Output stays on for the set time once the trigger/input is removed (mode depends on model: control-voltage triggered, contact-triggered, or power-off with storage).
• Supply Range: Universal inputs typically 12–240 V AC/DC (model dependent) for simplified stocking.
• Time Ranges: Milliseconds to hours via front dials or digital keys; fine/coarse ranges selectable.
• Outputs: SPCO or DPCO relay contacts; solid-state options available for high switching life.
• Accuracy & Repeatability: Tight tolerance over temperature; status LEDs for power, timing, and relay state.
• Mounting: 35 mm DIN rail; selected models allow panel/surface mounting.
• Protection: EMC-hardened designs with isolation and surge protection; conformal coating on some variants.
• Compliance: CE and RoHS; many units available with UL/CSA approvals.

✅ Benefits:

• Assured run-on period for fans, pumps, and conveyors after stop command.
• Prevents nuisance trips by releasing loads in a controlled, timed manner.
• Universal voltage variants reduce SKU count and simplify spares.
• Clear indication speeds commissioning and diagnostics.
• Robust contacts handle inductive loads common in machinery and HVAC.

🚀 Applications:

• Fan purge after burner shutdown; extraction run-on in HVAC.
• Pump anti-water-hammer sequencing and valve closing delays.
• Conveyor clearing after e-stop reset or stop command.
• Lighting exit delay and access control hold-open timing.
• General machinery where delayed drop-out improves safety or quality.

Off-delay timers deliver predictable, safe power-off delays for industrial controls, helping engineers achieve clean stop sequences and reliable machine behaviour.

Related Timing Categories

• On-Delay Timers
• Multi-Function Timers
• Star–Delta Timers
• Brown Out (Mains Restoration) Timers

FAQs

• Q: What is the difference between on-delay and off-delay?
  A: On-delay delays the turn-on of the output after the input arrives. Off-delay maintains the output for the set time after the input is removed.
• Q: How do I select an off-delay timer for inductive loads?
  A: Check contact rating for AC-15/DC-13 loads, allow margin for inrush, and consider RC snubbers or solid-state outputs for frequent switching.