Time Delay Relays

Part Number	Description / PDF	Quantity
LT4H-DC24VS Panasonic	RELAY TIME DELAY 999.9HR 5A 250V	12717
PM4HA-H-AC240VSW Panasonic	RELAY TIME DELAY 500HRS 5A 250V	0
S1DXM-A2C60M-DC24V Panasonic	RELAY TIME DELAY 60MIN 7A 250V	3
LT4H-AC240V Panasonic	RELAY TIME DELAY 999.9HR 5A 250V	39196
PM4HM-H-AC240VSW Panasonic	RELAY TIME DELAY 500HRS 5A 250V	3
LT4H-AC24V Panasonic	RELAY TIME DELAY 999.9HR 5A 250V	5
LT4HW-AC240V Panasonic	RELAY TIME DELAY 9999HRS 5A 250V	33
LT4HT-DC24VS Panasonic	RELAY TIME DELAY 999.9H 0.1A 30V	18
S1DXMA2C10HAC240V Panasonic	RELAY TIME DELAY 10HRS 7A 250V	5
PM4HA-H-AC240V Panasonic	RELAY TIME DELAY 500HRS 5A 250V	66138
LT4H-AC240VS Panasonic	RELAY TIME DELAY 999.9HR 5A 250V	413
PM4HW-H-AC240V Panasonic	RELAY TIME DELAY 500HRS 5A 250V	2
LT4HL8-AC24V Panasonic	RELAY TIME DELAY 999.9HR 5A 250V	5
PM4HA-H-24VSW Panasonic	RELAY TIME DELAY 500HRS 5A 250V	11
PM4HF8-M-DC12V Panasonic	RELAY TIME DELAY 10MIN 3A 250V	0
LT4HL8-DC24V Panasonic	RELAY TIME DELAY 999.9HR 5A 250V	19
LT4HW8-AC240V Panasonic	RELAY TIME DELAY 9999HRS 5A 250V	35
S1DXM-A2C10M-AC24V Panasonic	RELAY TIME DELAY 10MIN 7A 250V	150
PM4HM-H-24V Panasonic	RELAY TIME DELAY 500HRS 5A 250V	2
PM4HF8-M-AC120V Panasonic	RELAY TIME DELAY 10MIN 3A 250V	9

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