MJGX-3 Three Phase Solid State Relay 40A 3-32VDC LED Indicator
MJGX-3 Three Phase Solid State Relay 40A 3-32VDC LED Indicator
MJGX-3 D4840A Three Phase Solid State Relay — Industrial-Grade Control with LED Indicator
The MJGX-3 D4840A Three Phase Solid State Relay is a robust, fully enclosed switching device engineered for demanding industrial automation environments. Rated at 40A load current with a 3–32VDC control input and 90–480VAC output, this SSR delivers silent, fast, and reliable switching — with zero mechanical wear. A built-in LED indicator gives instant visual confirmation of the relay's on/off state, simplifying monitoring and diagnostics on the factory floor. Made in Mainland China.
Key Features
- Fully Enclosed Structure: Engineered to resist shock, moisture, and corrosion for long-lasting industrial performance.
- Superior Contact Quality: Rust-resistant, durable connections ensure consistent and dependable switching operation.
- Anti-Oxidation Heat-Dissipation Base Plate: Specially plated cooling base with a fine finish promotes efficient thermal management, preventing overheating during sustained use.
- Flame-Retardant Protective Shell: High-temperature-resistant housing provides fire, dust, and vibration-loosening protection.
- LED Status Indicator: Built-in LED provides at-a-glance confirmation of relay activation — no guesswork needed.
- Wide Industrial Compatibility: Ideal for petrochemical equipment, pharmaceutical and food machinery, packaging systems, textile machinery, plastic processing, CNC machine tools, and broader automation control applications.
- Bolt-Fixation Mounting: Secure and straightforward installation on DIN rails, panels, or heat sinks.
Technical Specifications
| Model | MJGX-3 D4840A |
| Phases | Three Phase |
| Load Current | 40A |
| Load Voltage | 90–480VAC |
| Control (Input) Voltage | 3–32VDC |
| Control Current | 15–30mA |
| On-State Voltage Drop | ≤1.8V |
| Off-State Leakage Current | ≤10mA |
| Off-State Time | ≤10ms |
| Dielectric Voltage | 2500VAC |
| Insulation Resistance | 1000MΩ / 500VDC |
| Ambient Temperature Range | -30°C to +75°C |
| Installation Method | Bolt Fixation |
| Status Indicator | LED |
| Weight | 340g |
| Country of Origin | Mainland China |
Package Includes
- 1× MJGX-3 D4840A Three Phase Solid State Relay
Important Notes
- Due to lighting and screen variation, the product color may differ slightly from images shown.
- Please allow ±1–3cm tolerance due to manual measurement.
- For safe installation and operation of solid state relays, always follow applicable electrical codes and standards. Refer to OSHA Electrical Safety Guidelines for best practices when working with industrial switching devices.
Frequently Asked Questions
Q: What is a three phase solid state relay and how does the MJGX-3 D4840A work?
A: A three phase solid state relay (SSR) is an electronic switching device that controls three-phase AC loads using a low-voltage DC control signal — with no moving mechanical parts. The MJGX-3 D4840A accepts a 3–32VDC input signal and switches a 90–480VAC, up to 40A load. Because switching is handled by semiconductor components (rather than mechanical contacts), SSRs offer faster response times, silent operation, and significantly longer service life compared to traditional electromechanical relays.
Q: Do I need an external heat sink for the MJGX-3 D4840A solid state relay?
A: While the MJGX-3 D4840A features a built-in anti-oxidation cooling base plate designed for heat dissipation, operating the relay at or near its maximum 40A load rating will generate significant heat. For continuous high-current applications, mounting the relay on an appropriately rated external aluminum heat sink is strongly recommended to maintain optimal performance and extend the lifespan of the unit.
Q: What types of industrial equipment is this three phase SSR compatible with?
A: The MJGX-3 D4840A is widely used in a broad range of industrial automation applications, including petrochemical equipment, pharmaceutical and food processing machinery, packaging lines, textile machinery, plastic extrusion machinery, and CNC machine tools. Any three-phase AC load requiring a low-voltage DC control interface within the relay's rated specifications can benefit from this SSR.
Q: What does the LED indicator on the MJGX-3 D4840A indicate?
A: The built-in LED indicator illuminates when the relay is in the "on" (conducting) state, providing a quick and clear visual confirmation that the control signal has been received and that the output circuit is active. This makes troubleshooting and system monitoring significantly easier, especially in complex control panel environments.