In modern industrial control systems, relays and contactors are the core components that enable motor start stop, logic control, and safety protection. ENTRELEC-SCHILE (now under Smiths Connectors) provides a complete solution from control relays to power contactors for fields such as metalworking, building automation, HVAC, and packaging machinery, thanks to its innovative dual auxiliary contact technology, forced guide contact structure, and highly reliable electromagnetic system. This article is based on the original product catalog, systematically organizing and deeply analyzing the technical characteristics, electrical parameters, selection codes, and application advantages of HL series control relays, DL series compact contactors, KL series small contactors, and supporting system components, providing authoritative and professional technical references for engineering designers.
Common core technologies
1.1 ENTRELEC-SCHILE Dual Auxiliary Contact Technology
All HL, DL, and KL series products adopt the dual auxiliary contact structure patented by ENTRELEC-SCHILE. Compared with standard contacts, this technology improves the reliability of control circuit contacts by 1000 to 10000 times, making it particularly suitable for low-level signal switching and high safety requirements. The dual auxiliary contacts provide positive guided contacts function, which complies with the German metal processing industry press safety specification ZH 1/457, ensuring that the contacts can still be forcibly disconnected in the event of welding.
1.2 Safety isolation and finger protection
All series meet the finger protection requirements of VDE 0106 Part 100, and the wiring terminal design ensures that operators cannot touch live parts. The coil and contact components achieve a maximum safe isolation of 400V AC, in compliance with DIN VDE 0106 Part 101 and subsequent revised A1 (draft 2/98), ensuring electrical isolation between the control circuit and the main circuit.
1.3 Dual frequency coil
Control relays and compact contactors come standard with 50/60 Hz dual frequency coils, eliminating the need to replace coils based on power frequency, simplifying inventory and selection. The coil voltage code follows the color identification of IEC 309-1 (e.g. 24V AC is purple, 24V DC is green). For N series contactors, single frequency coils (50Hz or 60Hz) can be provided.
1.4 Convenient wiring design
All terminals are equipped with plus/minus screws and self elevating clamps. The clamps are in the "open" position when leaving the factory, allowing for direct insertion of wires and tightening, greatly improving wiring efficiency. The terminal space is ample and can accommodate cables ranging from 2 × 6 mm ² to 25 mm ².
1.5 Installation method
All products support 35mm DIN rail card mounting, while reserving screw fixing holes (diameter 4mm) to adapt to different control cabinet layouts.
HL series control relay
The HL series control relay offers two basic specifications: 4-pole and 8-pole, which can be expanded to 8 contacts through additional auxiliary contact modules. This series is suitable for control circuits that require high contact reliability, such as programmable controller output isolation, signal amplification, and safety interlock circuits.
2.1 Model and Contact Configuration
HL 4 KD: 4-pole control relay, providing multiple contact combinations:
HL 4 KD-C-311:3 normally open+1 normally closed
HL 4 KD-C-221:2 normally open+2 normally closed
HL 4 KD-C-401:4 normally open+0 normally closed
HL 8 KD: 8-pole control relay, providing:
HL 8 KD-C-441:4 normally open+4 normally closed
HL 8 KD-C-531:5 normally open+3 normally closed
HL 8 KD-C-621:6 normally open+2 normally closed
HL 8 KD-C-711:7 normally open+1 normally closed
HL 8 KD-C-801:8 normally open+0 normally closed
2.2 Coil parameters and power consumption
AC coil: power consumption of only 6.5/8.8 VA, can be directly driven by a programmable controller
DC coil: power consumption 3W (standard) or 1.8W (interface type KHi)
Dual frequency coil: 50/60 Hz universal
Standard voltage: AC 24V/42V/110V/230V/400V; DC 24V/110V/220V (other voltages can be customized)
2.3 Interface type control relay KHi
The KHi series is an interface relay with DC operation, built-in coil suppressor, and LED operating status indication. The working voltage range of its coil is 0.7 to 1.3 times the rated voltage, with a power consumption of only 1.8W, and can be directly driven by the PLC output module. This series only allows the addition of 2-pole auxiliary contact modules. Model example:
KHiS-311:3 normally open+1 normally closed
KHiS-221:2 normally open+2 normally closed
KHiS-401:4 normally open+0 normally closed
2.4 Contact Rating and Safety Characteristics
Rated thermal current Ith: 10A
Forced opening of contacts: compliant with ZH 1/457
Terminal number: in accordance with DIN EN 50 011 standard
Weight: Approximately 0.18kg (screw terminal type) to 0.235kg (interface type)

DL series compact contactor
The DL series covers motor control applications ranging from 4 kW to 18.5 kW (AC-3 load, 400V), offering multiple versions including AC operation, DC operation, and DC switching (for DC loads). All models are integrated with ENTRELEC-SCHILE dual auxiliary contacts and can be equipped with additional auxiliary contact modules as needed.