KRDB420 - KRDB Series

Series: KRDB Questions? Contact Littelfuse Support
Littelfuse Delay on Break timers
The KRDB Series is a compact time delay relay measuring only 2 in. (50.8 mm) square. Its microcontroller timing circuit provides excellent repeat accuracy and stability. Encapsulation protects against shock, vibration, and humidity. The KRDB Series is a cost effective approach for OEM applications that require small size, isolation, reliability, and long life.


Operation (Delay-on-Break)
Input voltage must be applied before and during timing. Upon closure of the initiate switch, the output relay 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 will energize 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.

Property (Mouseover for details) Value
Input Voltage (V) 120VAC
Input Tolerance (%) -20% - 10%
Input AC Line Frequency (Hz) 50/60Hz
Output Type Isolated relay contacts
Output Form SPDT
Output Load Rating (VA) 10A resistive @ 125VAC; 5A resistive @ 230VAC and 28VDC; 1/4hp @ 125VAC
Time Delay Type Microcontroller with watchdog circuitry
Time Delay Range 0.1 - 10s onboard adjustable
Time Delay Tolerance (%) ±5%
Reset Time (ms) ≤150ms
Initiate Time (ms) ≤40ms
Repeat Accuracy (%) ±0.5% or 20ms whichever is greater
Setpoint vs Ambient Temperature and Operating Voltage (%) ≤ ±5%
Switching Voltage Maximum (V) 250VAC
Insulation Resistance ≥100 MΩ
Isolation Voltage (V) ≥1500V RMS input to output
Circuitry Encapsulated
Life Mechanical - 1 x 107; Electrical - 1 x 105
Power Consumption ≤2VA
Termination Type 0.25 in. (6.35mm) male quick connect terminals
Mounting Method Surface mount with one #10 (M5 x 0.8) screw
Operating Temperature -40° to 60°C (-40°F to 140°F)
Storage Temperature (F/C) -40° to 85°C (-40°F to 185°F)
Humidity 95% relative non-condensing
Dimensions 2.00 x 2.00 x 1.21 in. (50.8 x 50.8 x 30.7mm)
Weight (lbs/g) ≅2.6oz (74g)
Sample capable No