Time Delay Relays

Part Number	Description / PDF	Quantity
HRDI421 Wickmann / Littelfuse	RELAY TIME DELAY 100SEC 30A 125V	2
ESDR420B4 Wickmann / Littelfuse	RELAY TIME DELAY SS RECYCLING	0
TDMB422D Wickmann / Littelfuse	RELAY TIME DELAY D.OM./D.O.B	2
TSDR610.2SA0.2S Wickmann / Littelfuse	RELAY TIME DELAY SOL ST RECYCLNG	117
KRDI121 Wickmann / Littelfuse	RELAY TIME DELAY INTERVAL	0
HRISW27I Wickmann / Littelfuse	RELAY TIME DELAY	0
KSDS1115SP Wickmann / Littelfuse	RELAY TIME DELAY 15SEC CHASSIS	1
TDMB411 Wickmann / Littelfuse	RELAY TIME DELAY D.OM./D.O.B	2
THD1B410.5S Wickmann / Littelfuse	RELAY TIME DELAY 1000MIN CHASSIS	0
TRM24D1X10 Wickmann / Littelfuse	RELAY TIME DELAY	0
KRDS424 Wickmann / Littelfuse	RELAY TIME DELAY SINGLE SHOT	8
TDR2A23 Wickmann / Littelfuse	RELAY TIME DELAY SOLID ST ON/OFF	0
TSD7412S Wickmann / Littelfuse	RELAY TIME DELAY SOL ST INTERVAL	2
TDBL24DL Wickmann / Littelfuse	RELAY TIME DELAY DIGI-SET D.O.B.	0
KRPSA22B Wickmann / Littelfuse	RELAY TIME DELAY PROGRAMMABLE	828
TSDS320N Wickmann / Littelfuse	RELAY TIME DELAY SINGLE SHOT	7
RS4A24 Wickmann / Littelfuse	RELAY TIME DELAY ON/OFF RECYCLNG	0
TS13115 Wickmann / Littelfuse	RELAY TIME DELAY VERSA D.O.M.	5
TRB120A3X600 Wickmann / Littelfuse	RELAY TIME DELAY	0
ESDR320A0P Wickmann / Littelfuse	RELAY TIME DELAY SS RECYCLING	0

Time Delay Relays

1. Overview

Time Delay Relays (TDRs) are control devices that execute switching operations after a predetermined time interval. They integrate timing functions into electrical systems to manage sequence operations, protect equipment, and optimize process efficiency. Modern industrial automation relies on TDRs for precise control in applications ranging from motor startups to complex manufacturing processes.

2. Main Types and Functional Classification

Type	Functional Characteristics	Application Examples
On-Delay Relay	Delays contact closure after power application	Motor soft start, conveyor belt synchronization
Off-Delay Relay	Delays contact opening after power removal	Fan cooling systems, oven shutdown sequences
Interval Timer	Controls fixed-duration outputs	Valve actuation, injection molding cycles
Repeat Cycle Timer	Alternates between on/off states	Conveyor indexing, periodic lubrication systems

3. Structure and Components

Typical TDR construction includes:

Enclosure: Flame-retardant polymer housing (IP20-IP67 ratings)
Electromagnetic System: Coil assembly with laminated iron core
Contact Mechanism: Silver alloy contacts (NO/NC configurations)
Timing Circuit: Analog RC circuits or digital microcontrollers
User Interface: Dial/potentiometer or digital display for setting adjustment

4. Key Technical Specifications

Parameter	Typical Range	Importance
Timing Range	0.1s-999h	Determines application flexibility
Accuracy	1% to 10ms	Critical for precision processes
Power Supply	12-240V AC/DC	Matches system voltage requirements
Contact Rating	5-30A resistive	Ensures load compatibility
Ambient Temp. Range	-20 C to +70 C	Operational reliability factor

5. Application Areas

Primary industries include:

Manufacturing: Press machine sequence control
Energy: Transformer cooling systems
Building Automation: HVAC fan delay control
Process Industry: Pump alternation systems
Transportation: Railway signal timing

Typical equipment integration: CNC machines, packaging lines, water treatment systems.

6. Leading Manufacturers and Products

Manufacturer	Key Product Series	Distinguishing Features
Siemens	3RP25/3RP15 series	DIN rail mounting, LED status display
Omron	H3CR-A/-M models	Multi-voltage capability, compact design
Schneider Electric	Tesys T-ModTime series	Modbus communication, 12 timing functions
AutomationDirect	DL-TDR series	Programmable via USB interface

7. Selection Recommendations

Key considerations:

Timing function type (ON/OFF delay, interval, etc.)
Environmental conditions (temperature, vibration)
Electrical requirements (voltage/frequency compatibility)
Mounting method (DIN rail, panel mount, socket mounting)
Agency approvals (CE, UL, CSA standards)

Case Study: A bottling plant successfully implemented Omron H3CR-M timers for conveyor synchronization, achieving 15% throughput improvement.

8. Industry Trends

Emerging developments include:

Integration with Industrial IoT (remote monitoring via Ethernet/IP)
Adoption of solid-state relay technology (SSR) for higher switching speeds
Energy-efficient designs meeting Ecodesign Directive 2019/1782
AI-enhanced predictive timing adjustment in smart manufacturing