CURRENT SSR
Description
The Denki Seigyo Analog Current SSR Series is designed for precision power control applications requiring smooth, proportional switching of AC or DC loads. Unlike conventional ON/OFF relays, these SSRs respond to analog current input signals to deliver variable output voltage or current, enabling precise regulation of heaters, motors, and lamps.
With high-reliability semiconductor switching, optical isolation, and fast response, Denki Seigyo SSRs ensure long operational life, low maintenance, and silent, arc-free performance in industrial control systems.

Features
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Linear proportional control based on analog current input (4–20 mA or 0–20 mA)
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Zero-cross or phase-angle control models available
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Optically isolated input for electrical noise immunity
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Fast response with no contact bounce or arcing
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Low leakage current and minimal output voltage drop
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Built-in over-temperature and surge protection
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Compact, DIN-rail and panel mountable enclosures
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Long service life with solid-state switching (no moving parts)
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Ideal for resistive, inductive, and heater load control
Specifications
| Item | Specification |
|---|---|
| Control Input Signal | 4–20 mA DC (optional 0–20 mA / 1–5 VDC) |
| Input Impedance | 250 Ω (typical) |
| Control Type | Phase control / Zero-cross |
| Load Voltage Range | 24–480 VAC (RMS) / 24–110 VDC (model dependent) |
| Load Current Rating | 5 A, 10 A, 25 A, 40 A, 60 A, 80 A |
| Turn-On Time | ≤1 ms (zero-cross type) |
| Turn-Off Time | ≤1/2 cycle (8.3 ms at 60 Hz) |
| Dielectric Strength | 2.5 kVAC (Input–Output), 1.5 kVAC (Output–Base) |
| Isolation Resistance | ≥100 MΩ at 500 VDC |
| Leakage Current (Off-State) | ≤10 mA (at rated voltage) |
| Voltage Drop (On-State) | ≤1.6 V RMS (at rated load current) |
| Operating Temperature | -20°C to +80°C (no condensation) |
| Cooling Method | Natural convection or with optional heat sink |
| Protection | Built-in surge absorber, overheat cutoff (optional) |
| Indicator | Power (Green LED), Output ON (Red LED) |
| Mounting Type | DIN-rail or panel mount |
| Housing Material | Flame-retardant PC (UL94-V0) |
| Weight | Approx. 150–250 g (depending on model) |
Model Selection Table
| Model | Control Signal | Load Voltage | Load Current | Control Type | Mounting | Cooling Option |
|---|---|---|---|---|---|---|
| DSSR-A05C | 4–20 mA | 24–280 VAC | 5 A | Zero-cross | Panel mount | Natural |
| DSSR-A25C | 4–20 mA | 24–480 VAC | 25 A | Zero-cross | DIN rail | With heat sink |
| DSSR-A40P | 4–20 mA | 24–480 VAC | 40 A | Phase control | Panel mount | Forced air |
| DSSR-A60P | 4–20 mA | 24–480 VAC | 60 A | Phase control | DIN rail | Forced air |
| DSSR-D10C | 4–20 mA | 24–110 VDC | 10 A | Linear control | Panel mount | Natural |
| DSSR-D25C | 4–20 mA | 24–110 VDC | 25 A | Linear control | Panel mount | With heat sink |
Applications
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Proportional temperature control for industrial heaters
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Dimming and intensity control for industrial lamps
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Variable-speed control for AC fans and motors
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Process automation systems requiring analog signal control
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OEM equipment, plastic molding, packaging, and drying machines
Optional Accessories
| Part Number | Description |
|---|---|
| DHS-200C | Compatible heat sink (200 mm, 0.4 °C/W) |
| DSC-420M | 4–20 mA signal converter module |
| DBR-24V | 24 VDC control power supply |
| DMH-SRL01 | Mounting rail and bracket kit |
Ordering Example
Model: DSSR-A25C
Description: Analog current solid state relay, 4–20 mA input, 25 A load, 24–480 VAC output, zero-cross control, DIN-rail mount




