Industrial Solid State Relay (SSR) Solutions

Fiicco offers two main SSR series:

• FCSR-SSR (Single-Phase): Current ratings 10A–120A. Types include AC-to-AC (SSR-AA), DC-to-AC (SSR-DA), DC-to-DC (SSR-DD), linear control 4-20mA input (SSR-LA), and variable resistor input (SSR-VA). Load voltage up to 380VAC (480V optional).
• FCSR-SSR-3 (Three-Phase): Current ratings 10A–200A. DC-to-AC (SSR-3-DA) and AC-to-AC (SSR-3-AA) types. Load voltage up to 480VAC.
• FCSR-HS (Heat Sinks): SSR-HS-1-S, SSR-HS-1-M, SSR-HS-1-L for single-phase; SSR-HS-3 for three-phase units.

All models feature zero-crossing control, heat sink separated design, and double surge resistance circuit with >10x surge current endurance.

Zero-crossing means the SSR turns ON only when the AC voltage crosses zero volts. This eliminates the voltage spike and electromagnetic interference (EMI) that would occur if the SSR switched at peak voltage.

Fiicco uses zero-crossing as standard across all SSR models because it:

• Greatly reduces electrical noise and interference with nearby equipment
• Minimizes stress on the load (especially inductive loads like motors and transformers)
• Extends the lifespan of both the SSR and the connected load
• Operate time: ≤0.5 cycles of load power +1ms
• Release time: ≤0.5 cycles of load power +1ms

For applications requiring immediate ON at any point in the AC cycle (random-on), contact Fiicco for custom options.

These refer to the control (input) signal type:

• SSR-XXAA (AC input): Controlled by an AC voltage signal of 80-250VAC. The SSR turns on when the AC control voltage is applied. Simple and common for use with PLCs, timers, and manual switches. Compatible with most industrial control systems without additional power supplies.
• SSR-XXDA (DC input): Controlled by a DC voltage signal of 3-32VDC. Requires a DC control source (PLC DC output, microcontroller, sensor). Lower power consumption on the control side. More precise and widely used in modern automation systems.

Both switch AC loads (24-380VAC). The output side is identical — only the input signal type differs. For three-phase models: SSR-3-AA uses 70-280VAC input; SSR-3-DA uses 3-32VDC input.

Choose based on your load current with a safety margin:

• Resistive loads (heaters, ovens): Select SSR rated at 1.5x the actual load current. Example: 20A heater → choose 30A SSR.
• Inductive loads (motors, transformers, solenoids): Select SSR rated at 2x the actual load current. Motors have high inrush current (6-10x running current). Example: 10A motor → choose 20A+ SSR.
• Capacitive loads: Select SSR rated at 2-3x the actual load current.

Fiicco SSR ratings: 10A, 25A, 40A, 60A, 80A, 100A, 120A (single-phase) and 10A–200A (three-phase). The heat sink separated design allows efficient thermal management at all current ratings.

Yes, SSRs generate heat because the TRIAC/SCR output has a voltage drop of approximately 1-2V across its terminals during conduction. The heat generated equals: Load Current × 1.5V.

Example: A 40A SSR switching 30A generates approximately 45W of heat that must be dissipated.

Fiicco SSRs feature a heat sink separated design for efficient thermal management. A proper heat sink is required when operating above approximately 50% of the rated current. Fiicco offers matching heat sinks:

• SSR-HS-1-S/M/L: For single-phase SSRs (S=small, M=medium, L=large)
• SSR-HS-3: For three-phase SSRs

Terminal fixed torque: 1.6-2.2N·m for secure mounting.

When an SSR is OFF, a small leakage current (≤10mA max on Fiicco SSRs) still flows through the semiconductor output. Unlike an electromagnetic relay (which has near-zero leakage when open), SSRs cannot provide complete circuit isolation in the OFF state.

Leakage current matters in these scenarios:

• High-impedance loads: A 10mA leakage through a 100kΩ load = 1V, which may be noticeable
• LED lighting: Some LED drivers may glow faintly when the SSR is off due to leakage current
• Safety-critical circuits: For complete isolation, add a mechanical contactor downstream

For most industrial heating and motor control applications, ≤10mA leakage is negligible. Other specs: dielectric strength 2500VAC 50/60Hz for 1min, insulation resistance ≥100MΩ.

Yes. Standard Fiicco SSRs support load voltages up to 380VAC. Models marked with 480V optional can be configured for 480V operation:

• SSR-XXAA: 24-380VAC standard, 480V optional (single-phase AC input)
• SSR-XXDA: 24-380VAC standard, 480V optional (single-phase DC input)
• SSR-XXDD: 24-220VDC load (single-phase DC output)
• SSR-3-XXAA / SSR-3-XXDA: 24-480VAC three-phase models available up to 200A

When specifying 480V models, confirm the voltage rating with your order. Standard models should not be used in 480V systems — always select the 480V option for North American and high-voltage applications.

These refer to the load (output) side type:

• SSR-DD (DC-to-DC): Switches DC loads. Input: 3-32VDC, Output: 24-220VDC. Used for DC motor speed control, battery charging systems, DC LED dimming, and solar power systems.
• SSR-DA (DC-to-AC): Switches AC loads using DC input signal. Input: 3-32VDC, Output: 24-380VAC. The most versatile and popular type for industrial automation, heating control, and AC motor switching.

Always match the output type to your load. SSR-DD cannot switch AC loads, and SSR-DA cannot switch DC loads — the internal semiconductor (MOSFET/IGBT for DC vs TRIAC/SCR for AC) is different.

Input side (control): Connect the control signal to the input terminals. For SSR-DA (DC input): apply 3-32VDC to turn on (e.g., 5V from PLC, 24V from power supply). For SSR-AA (AC input): apply 80-250VAC to turn on.

Output side (load): Connect the load in series with the SSR output terminals. For AC loads: connect L and N through the SSR output. Terminal fixed torque: 1.6-2.2N·m.

Important wiring tips:

• Always wire the SSR's input and output circuits independently — they are isolated by the internal optocoupler
• Use appropriate wire gauge for the load current (follow local electrical codes)
• Mount the SSR on a heat sink for currents above 50% of rated value
• Do not exceed the dielectric strength rating: 2500VAC 50/60Hz for 1min
• Operating ambient temperature: -30°C to +80°C, humidity: 45-85%RH

Yes. Fiicco provides comprehensive OEM and ODM services for solid state relays:

• Custom logo and brand labeling on the SSR housing and packaging
• Custom input/output voltage combinations beyond the standard options
• Custom current ratings for volume orders
• Integrated solutions: SSR + heat sink + fuse holder assemblies
• Random-on (instant switching) variants for phase-angle control applications
• Special voltage ratings (480V standard, etc.)
• Volume pricing for distributor and OEM orders

With our own factory and 10+ years of manufacturing experience since 2013, we support both small custom runs and high-volume production. Contact us at fiicco.com/contact to discuss your requirements.