© 2016 Littelfuse Protection Relays & Controls

Time Delay Relays

Dedicated - Delay-on-Break

Rev: 1-A-062216

www.littelfuse.com/thdb

THDB SERIES

Description

The THDB Series combines accurate timing circuitry with high

power, solid-state switching. It can switch motors, lamps, and

heaters directly without a contactor. You can reduce labor,

component cost, and increase reliability with these small,

easy-to-use, timers.

Operation (Delay-on-Break)

Input voltage must be applied before and during timing. Upon

closure of the initiate switch, the output energizes. The time

delay begins when the initiate switch is opened. The output

remains energized during timing. At the end of the time delay,

the output de-energizes. The output energizes if the initiate

switch is closed when input voltage is applied.

Reset: Reclosing the initiate switch during timing resets the time

delay. Loss of input voltage resets the time delay and output.

Features & Benefits

FEATURES

BENEFITS

Microcontroller based

Repeat accuracy + / - 0.5%,

Factory calibration + / - 1%

High load currents up

to 20A, 200A inrush

Allows direct operation of motors, lamps and

heaters without a contactor

Totally solid state

and encapsulated

No moving parts to arc and wear out over time and

encapsulated to protect against shock, vibration,

and humidity

Metalized

mounting surface

Facilitates heat transfer in high current applications

Compact, low

cost design

Allows flexibility for OEM applications and reduces

labor and components costs

Accessories

P1004-95, P1004-95-X Versa-Pot

Panel mountable, industrial potentiometer

recommended for remote time delay adjustment.

P0700-7 Versa-Knob

Designed for 0.25 in (6.35 mm) shaft of

Versa-Pot. Semi-gloss industrial black finish.

P1015-64 (AWG 14/16)

Female Quick Connect

These 0.25 in. (6.35 mm) female terminals are

constructed with an insulator barrel to provide

strain relief.

P1015-18 Quick Connect to Screw Adapter

Screw adapter terminal designed for use with

all modules with 0.25 in. (6.35 mm) male quick

connect terminals.

Wiring Diagram

Ordering Information

MODEL

INPUT

VOLTAGE

ADJUSTMENT

TIME DELAY

OUTPUT

RATING

THDB421A

120VAC

External

1 - 100s

6A

THDB434C

120VAC

Onboard

1 - 100m

20A

If you don’t find the part you need, call us for a custom product 800-843-8848

L1

N/L2

V = Voltage

UTL = Optional Untimed

Load

L =Timed Load

S1 = Initiate Switch

RT is used when external

adjustment is ordered.