Content last revised on November 9, 2025
Crydom HD4890 90A/48-530VAC Solid-State Relay | Industrial Zero-Crossing Control
The Crydom HD4890 is a high-performance Solid-State Relay (SSR) specifically engineered for demanding industrial environments. It delivers an exceptional 90 Amp continuous current rating with a wide output voltage range of 48-530 VAC, enabling reliable control of heavy-duty heating elements, industrial motors, and lighting circuits. The HD4890’s proven reliability, extended service life, and advanced zero-crossing technology make it the standard choice for automation, HVAC, and power control applications.
At a Glance:
- Load Current: Robust 90A capability for managing high-power loads.
- Control Voltage: Wide-ranging 4–32 VDC control input, ensuring direct compatibility with standard PLCs or microcontrollers.
- Output Voltage: Wide 48-530 VAC operating range.
- Switching Mode: Zero-Crossing switching for effective reduction of electromagnetic interference (EMI).
- Certifications: Backed by international safety approvals, including UL, CSA, and TÜV.
Core Technical Strengths: Engineered for Stability
90A High-Current and 48-530 VAC Compatibility
The HD4890 is designed from the ground up to handle serious industrial loads. Its 90A rating allows it to directly switch large resistive or inductive loads. The **48-530 VAC** output voltage ensures broad compatibility with various regional industrial power specifications, offering maximum flexibility for global deployment.
Zero-Crossing Switching Technology
This relay utilizes zero-crossing technology, meaning it only turns ON or OFF when the AC voltage waveform is near the zero-point. This critical feature dramatically minimizes voltage transients and reduces radio frequency interference (RFI/EMI), protecting sensitive control electronics and adjacent components. This is fundamental to maintaining stability in high-reliability industrial systems. We recommend reviewing external resources on Zero-Cross or Random Relay: What are the differences for deep technical insight.
Wide-Range DC Control Input
The generous 4–32 VDC input range simplifies control system design. It ensures that the HD4890 can be directly driven by standard low-voltage DC power sources or the digital output ports of modern automation equipment, such as PLCs (Programmable Logic Controllers) and DCS (Distributed Control Systems).
Typical Application Scenarios
- Industrial Heating Systems: Used for precise control of high-power heating elements in ovens, molding machines, and packaging equipment.
- Motor Control: Ideal for switching small motors or auxiliary circuits of larger industrial motors where frequent cycling is required.
- Lighting and Dimming: Provides quiet, reliable switching for high-wattage lighting circuits in large commercial facilities or specialized venues.
- HVAC/R: Employed to control compressors, heating elements, and fans in critical heating, ventilation, air conditioning, and refrigeration systems.
Key Technical Specifications
| Parameter | Value |
| Manufacturer | Crydom |
| Model | HD4890 |
| Output Rated Current | 90 Amps (90A) |
| Output Voltage Range | 48-530 VAC |
| Input Control Voltage | 4 – 32 VDC |
| Switching Mode | Zero-Crossing |
| Zero-Crossing Voltage | < 25 V |
| Surge Current Rating (10 ms) | $1200 \text{ A}_{pk}$ |
| Typical Applications | Industrial Heating, Motor, Lighting Loads |
| Certifications | UL, CSA, TUV |
Summary
The Crydom HD4890 Solid-State Relay is an industry-standard solution for industrial applications demanding high reliability, robust **90A** current control, and minimal EMI disturbance. Its wide **48-530 VAC** operating range and mature zero-crossing technology make it a safe and dependable choice for your most critical systems.
