Littelfuse delivers vital products to address customer needs for protecting and safely controlling electrical power. Our single-function & control relays product portfolio includes 19 series of delay-on-make time-delay relays that start delay cycles when input voltages are applied. Each version boasts excellent repeat accuracy. Available features include microcontroller-based circuitry, solid-state components, encapsulation, and LED indicators.

 

Features

• Ac input voltages from 24 V ac to 240 V ac
• Dc input voltages from 12 V dc to 240 V dc
• Fixed or selectable time delays from 100 ms to 1200 s
• Repeat accuracy of ±0.5 % or 20 ms, whichever is greater
• Operate at temperatures ranging from –40 °C to +85 °C
• Reset times ≤ 150 ms
• Initiate times ≤ 20 ms
• Time delays vs. temp. & voltage ≤ ±10 %
• Ac line frequency/Dc ripple of 50/60 Hz with accuracy within 10 %
• UL Listed or UL Recognized

 

Benifits

• Connect easily in series with contactors, relays, valves, and solenoids
• Available with DPDT output circuitry, SPDT output circuitry, normally open (Form A) contacts, or normally closed (Form B) contacts
• Available with digital or microcontroller-based circuitry
• Available with customized delays
• Compact designs and low weight

Model	Image	Description
ERDM Series		The ERDM Series is a combination of digital electronics and a reliable electromechanical relay. These devices offer a DPDT relay output for relay logic circuits, and isolation of input to output voltages. Cost effective for OEM applications, such as random starting, sequencing ON, switch de-bouncing, anti-short cycling, and other common delay-on-make applications.
HRDM Series		The HRDM Series combines an electromechanical relay output with microcontroller timing circuitry. It offers 12 to 230V operation in five ranges and factory fixed, onboard, or external adjustable time delays with a repeat accuracy of ±0.5%. The output contact rating allows for direct operation of heavy loads, such as compressors, pumps, blower motors, heaters, etc.
KRDM Series		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.
KRPS Series		The KRPS Series is a factory programmed time delay relay available with 1 of 15 functions and measures only 2 inches square. The KRPS offers a wide range of fixed, onboard, or externally adjustable time delays.
KSD Series		The KSD1 Series features two-terminal, series-connection with the load. The KSD1 Series is an ideal choice for delay-on-make timing applications. This series is designed for general purpose commercial and industrial applications where a small, cost effective, reliable solid-state timer is required.
KSDU Series		The KSDU Series are encapsulated solid-state, delay-on-make timers that combine digital timing circuitry with universal voltage operation. The KSDU Series is factory fixed from 0.1s to 10,230s and does not include the DIP switch. These series are excellent choices for process control systems and OEM equipment.
KSPS Series		The KSPS Series is a factory programmed module available in any 1 of 14 standard functions. The KSPS Series offers a single, fixed, externally or onboard adjustable time delay. The 1A steady, 10A inrush rated solid-state output provides 100 million operations typical.
MSM Series		The MSM Series replaces bi-metal type timing with reliable solid-state circuitry. There are no moving parts to arc or wear. It is a cost effective solution for OEM designers. It is available for printed circuit board mounting or surface mounting with a removable bracket and wire leads.
ORM Series		The ORM Series features open PC board construction for reduced cost. It has isolated, 10A, DPDT relay contacts and all connections are 0.25 in (6.35 mm) male quick connect terminals. The time delay may be ordered as factory fixed, onboard knob, or external adjustment. Time delays from 0.05 - 300 seconds.
PRLM Series		The PRLM series is designed for use in non-critical timing applications. It offers low cost, fixed or knob adjustable timing control, full 8 A relay output, and onboard LED indication. The onboard LED indicates whether or not the unit is timing (flashing LED) as well as the status of the output.