Littelfuse KRDM221, KRDM Series, 24VAC/DC, On-Delay Time Delay Relay SPDT (1 Form C) 1 Sec ~ 100 Sec Delay 10A @ 125VAC Chassis Mount
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The KRDM Series is a compact time delay relay measuring only 2 in. (50.8 mm) square. Its solid-state timing circuit provides excellent repeat accuracy and stability. Encapsulation protects against shock, vibration, and humidity. The KRDM Series is a cost effective approach for OEM applications that require small size, isolation, reliability, and long life.
Operation (Delay-on-Break)
Upon application of input voltage, the time delay begins. The output is de-energized before and during the time delay. At the end of the time delay, the output relay energizes and remains energized until input voltage is removed.
Reset: Removing input voltage resets the time delay and output.
Specifications
| Time Delay | |
| Range | 0.1s - 100m in 5 adjustable ranges or fixed |
| Repeat Accuracy | ±0.5% or 20ms, whichever is greater |
| Tolerance (Factory Calibration) | ≤ ± 5% |
| Recycle Time | ≤ 150ms |
| Time Delay vs Temp. & Voltage | ≤ ±5% |
| Input | |
| Voltage | 12, 24 or 110VDC; 24, 120 or 230VAC |
| Tolerance |
12VDC & 24VDC/AC -15% - 20% 110VDC, 120 or 230VAC -20% - 10% |
| AC Line Frequency/DC Ripple | 50/60 Hz / ≤ 10% |
| Power Consumption | AC ≤ 2VA; DC ≤ 2W |
| Output | |
| Type | Isolated relay contacts |
| Form | SPDT |
| Rating (at 40°C) |
10A resistive @ 125VAC; 5A resistive @ 230VAC & 28VDC; 1/4 hp @ 125VAC |
| Max. Switching Voltage | 250VAC |
| Life (Operations) | Mechanical - 1 x 10⁷ ; Electrical - 1 x 10⁵ |
| Protection | |
| Polarity | DC units are reverse polarity protected |
| Circuitry | Encapsulated |
| Isolation Voltage | ≥ 1500V RMS input to output |
| Insulation Resistance | ≥ 100 MΩ |
| Mechanical | |
| Mounting | Surface mount with one #10 (M5 x 0.8) screw |
| Dimensions |
H 50.8 mm (2”) W 50.8 mm (2”) D 30.7 mm (1.21”) |
| Termination | 0.25 in. (6.35 mm) male quick connect terminals |
| Environmental | |
| Operating/Storage Temperature | -20° to 60°C / -40° to 85°C |
| Humidity | 95% relative, non-condensing |
| Weight | ≅ 2.6 oz (74 g) |