1PC TIANBO HJQ-15F-1-S-Z 24VDC Power Relay 5Pins ~~US

TIANBO · Automotive Relay · HJQ-15F Series · 24VDC Coil · In stock

What Is the TIANBO HJQ-15F-1-S-Z 24VDC Power Relay?

The TIANBO HJQ-15F-1-S-Z is a 5-pin SPDT (Single Pole Double Throw) electromagnetic relay with a 24VDC coil. It operates as an electrically controlled switch — a small current through the coil energizes a magnet that physically throws a set of contacts, connecting the common terminal to either the normally-open or normally-closed output. TIANBO produces relays that are commonly deployed in automotive electrical systems, PLC I/O expansion boards, marine DC panels, and industrial machine controls where a low-power signal must safely command a higher-power load.

In short: A 24V DC-controlled electromechanical switch with both normally-open and normally-closed outputs — the standard building block for relay logic, signal isolation, and load switching in vehicle and industrial DC circuits.

Understanding the Pin Layout and How to Wire It

1. Coil Terminals (Pin 85 and Pin 86)

Apply 24VDC across these two pins to energize the relay. If the relay body shows a diode symbol or + / - markings near these pins, polarity matters — the relay has an internal flyback diode and must be wired with correct polarity. If no markings are present, the coil is non-polarized and either direction works. When driving the coil from a transistor or microcontroller, always add an external flyback diode (1N4007, cathode to positive) across the coil to absorb the inductive kickback.

2. The Three Load Pins (30, 87, 87a)

Pin 30 is the common — your power source connects here. Pin 87 is normally-open — it connects to Pin 30 only when the coil is energized (relay ON). Pin 87a is normally-closed — it connects to Pin 30 only when the coil is de-energized (relay OFF). For a standard on/off load, use pins 30 and 87. For a changeover circuit (e.g., switching between main and backup power), all three load pins are used.

3. Contact Life and Load Types

Silver alloy contacts in the HJQ-15F are rated for tens of thousands of cycles at full resistive load. Inductive loads (motors, solenoids, contactor coils) cause arcing that erodes contacts faster. For inductive DC loads, install a snubber (RC network) or MOV across the load terminals to quench the arc and extend relay life. If your application cycles the relay more than once per minute continuously, derate the switched current by at least 30% below the maximum contact rating.

Key Specifications

Where This Relay Is Used

• Vehicle lighting upgrades: Driving lights, light bars, and fog lamps where factory wiring is inadequate for added current draw.
• Marine DC distribution: Bilge pumps, navigation lights, and battery isolation in 24V boat electrical systems.
• PLC interposing relay: When a PLC transistor output rated at 0.5A must switch a 10A solenoid or contactor coil.
• Off-grid solar: Load disconnect and dump load control in 24V battery bank systems.
• Industrial signal towers: Switching high-brightness LED stack lights or audible alarms from a low-current control signal.

Frequently Asked Questions

How do I bench-test this relay before wiring it into my system?

Set a multimeter to continuity mode. De-energized: Pin 30 should beep with Pin 87a and show open to Pin 87. Apply 24VDC to Pins 85/86 — you should hear a crisp click. Now Pin 30 should beep with Pin 87 and show open to Pin 87a. If the relay chatters, hums loudly, or fails to switch, the coil voltage may be incorrect or the relay may be damaged. Use a current-limited bench supply to avoid burning the coil during testing.

Will this relay work on a 12V car instead of 24V?

No — a 24VDC coil needs roughly 24V to pull in reliably. At 12V, the magnetic force is about 25% of design strength, which typically results in failure to close or intermittent chatter that overheats the coil. For 12V automotive systems, you need a 12VDC-rated coil. Contact us with your specs and we can source the correct voltage variant.

What socket or connector type does this relay accept?

The HJQ-15F uses a standard automotive/industrial ISO relay footprint. A 5-pin socket with 6.3mm female quick-connect terminals fits directly. For one-off installations, crimp individual 6.3mm (1/4-inch) female spade connectors onto your wires and push them onto the relay tabs. For production or vibration-prone environments, use a latching socket with a mounting bracket. Browse our collections for sockets and accessories.

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