HONEYWELL GR-4C-DC24V

Description

Product Description

The HONEYWELL GR-4C-DC24V is a robust and reliable general-purpose electromechanical relay designed for a wide array of industrial control and automation applications. This relay functions as a critical interface device, allowing low-power control signals from a PLC output module, controller, or switch to safely and effectively switch higher-power electrical loads. The core function of the HONEYWELL GR-4C-DC24V is to provide galvanic isolation and power amplification between the sensitive control circuit (24V DC) and the load circuit (up to 10A, 250V AC/30V DC). Its 4-pole Changeover (4 Form C) contact configuration offers exceptional flexibility for complex switching logic. Integrating the HONEYWELL GR-4C-DC24V into a control panel enables safe and reliable operation of motors, solenoids, lamps, heaters, and other actuators, protecting the PLC from inductive kickback and high-current faults. Its transparent dust cover allows for visual inspection of contacts and coil status, making it a practical choice for maintenance-friendly designs.

Technical Parameters and Features

• Device Type: General Purpose Electromechanical Relay.
• Coil Specifications:
  • Coil Voltage: 24 Volts DC (as indicated by the -DC24V suffix).
  • Coil Power Consumption: Typically in the range of 0.9 to 1.4 Watts, depending on the specific variant.
• Contact Specifications:
  • Contact Configuration: 4 Form C (4PDT – Four Pole Double Throw). This provides 4 independent sets of changeover contacts (Common, Normally Open, Normally Closed per pole).
  • Contact Material: Silver Alloy, suitable for both AC and DC switching.
  • Contact Rating: The GR-4C is rated for 10 Amperes at 250V AC or 30V DC for resistive loads. Ratings for inductive loads (e.g., motor, solenoid coils) are significantly lower and must be derated.
  • Electrical Life: Typically tens of thousands of operations at rated load.
• Termination: Screw terminal connections for both coil and contact wiring.
• Mounting: Standard DIN-rail mount (35mm) or panel mount via a socket or base.
• Indicators: Features a mechanical flag indicator to show the contact position (energized/de-energized status).
• Enclosure: Typically has a transparent polycarbonate dust cover meeting IP40 rating.
• Standards: Complies with relevant international standards such as IEC 61810-1, UL 508, and CSA.

Advantages and Key Features

• High Contact Capacity and Flexibility: The 4-pole changeover (4 Form C) configuration of the HONEYWELL GR-4C-DC24V provides unparalleled wiring flexibility, allowing it to control multiple circuits, perform logic (e.g., break-before-make), or parallel contacts for higher current capacity in a single device.
• Robust and Durable Construction: Built with industrial-grade materials, this relay offers excellent mechanical life (millions of operations) and reliable electrical performance, even in environments with vibration and moderate temperature fluctuations.
• Clear Visual Status Indication: The integrated mechanical flag and transparent cover allow for instant visual confirmation of the relay’s operational state from a distance, significantly aiding in troubleshooting and panel diagnostics.
• Excellent Isolation: Provides robust galvanic isolation (typically 4kV) between the low-voltage DC coil and the switched load circuit, protecting sensitive control electronics from transients and faults on the load side.
• Proven Brand Reliability: Honeywell is a trusted name in industrial components. The GR-4C-DC24V relay benefits from consistent manufacturing quality and wide global availability.

Application Case Studies in Various Fields

• Packaging Machinery: Used to interface a 24V PLC output with 240V AC motor starters and solenoid valves for product handling. One GR-4C-DC24V relay can control the forward/reverse circuit of a small conveyor motor using two changeover contacts.
• HVAC Control Panels: Employed in building management systems to switch fan coils, pumps, and damper actuators. The 4-pole design allows one relay to control multiple stages of a multi-speed fan or several dampers in a zone.
• Commercial Appliance Control: Found in commercial laundry or kitchen equipment to control heating elements, water inlet valves, and drain pumps, where the 10A rating is well-suited for these resistive and inductive loads.
• Automated Test Stands: Used to switch instrument power, signal paths, or device-under-test (DUT) supplies under program control from a data acquisition system or small controller.

Comparison with Competing Products

Compared to solid-state relays (SSRs) or lower-pole-count relays, the HONEYWELL GR-4C-DC24V has distinct operational characteristics:

1. Electromechanical vs. Solid-State: Unlike an SSR, the GR-4C-DC24V has physical contacts, resulting in a voltage drop and potential for arcing and contact wear. However, it offers superior resistance to surge currents, zero leakage current when off, and can switch a wider range of AC/DC voltages without concern for polarity.
2. Pole Count & Flexibility: With its 4 Form C contacts, it offers significantly more switching capability in one unit compared to common 1-pole or 2-pole general-purpose relays (e.g., Finder 40 series, Omron MY series), reducing the number of relays and DIN-rail space needed for complex logic.
3. Cost-Effectiveness for Medium Duty: For applications requiring multiple contact sets and switching frequencies in the range of a few operations per minute to several per hour, the HONEYWELL GR-4C-DC24V is often more cost-effective than using multiple single-pole SSRs or PLC output modules with high current ratings.

Selection Advice and Important Notes

• Derate for Inductive and Lamp Loads: The 10A rating is for resistive loads. For inductive loads (motors, solenoids), derate by at least 50-75%. For incandescent lamp loads (high inrush current), derate significantly (often to 10-20% of the resistive rating). Always consult the derating curves in the datasheet.
• Use Protective Circuits for Inductive Loads: Always use a flyback diode (for DC coils) or a snubber circuit (for AC coils/loads) across the inductive load controlled by the GR-4C-DC24V to suppress voltage spikes and protect the relay contacts from premature welding or erosion.
• Verify Coil Voltage Compatibility: Ensure your control power supply is a stable 24V DC. Applying a voltage outside the tolerance (typically +/- 10%) can cause the coil to overheat (if too high) or fail to pull in reliably (if too low).
• Consider Switching Frequency: Electromechanical relays like the HONEYWELL GR-4C-DC24V have a limited mechanical and electrical life. For high-frequency switching (more than a few operations per minute), a solid-state relay (SSR) is a more suitable choice.
• Inspect and Maintain: Periodically inspect the relay’s transparent cover for signs of contact arcing (blackening) or overheating (melting). The mechanical flag indicator is a quick way to verify coil operation during testing.

SGLA34AT0400 PLC
SKLA36AT0800 PLC
PR9350/02+CON021 PLC
6DD1661-0AD0
2711P-B7C4A8 PLC
PCI2000PFB PLC
VPM-8100X-000 PLC
CIMREX-67