Omron G3NB-240B-1 DC5-24V — 40 A Zero-Cross SSR, 24-220 VAC
SKU: G3NB-240B-1 DC5-24VUSD 8.50
Compact solid-state relay with 40 A load current at 24-220 VAC, DC 5-24 V control input, zero-cross switching, phototriac isolation, screw terminals. Requires Y92B-N150 heat sink for >6 A continuous. 410 A peak inrush withstand for transformer-coupled and heater loads.
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Product Overview
The G3NB-240B-1 DC5-24V is Omron's 40 A-class compact solid-state relay (SSR) for OEM high-volume AC load switching applications, the bigger sibling of the already-done G3NB-210B-1 (10 A) and G3NA-210B-UTU (10 A, batch 16). It uses a zero-cross phototriac output stage to switch 24-220 VAC loads at up to 40 A continuous (with the required Y92B-N150 heat sink), with a peak inrush capability of 410 A for the first AC cycle — sufficient for transformer-coupled loads, large heater banks, and motor starters. The DC 5-24 V control input draws 4-6 mA, making it directly compatible with CJ1W-OD212 PNP sourcing outputs (already done in our catalog) and most PLC transistor outputs.
Why zero-cross switching matters for 40 A loads
The G3NB-240B-1's zero-cross switching turns the AC load ON only when the AC voltage is near the zero-crossing point (typically within ±15 V of zero). This eliminates the inrush current spike that would occur if the SSR turned on at the peak of the AC cycle (where the instantaneous voltage is 170 V on a 120 VAC line or 340 V on a 240 VAC line).
Heat sink sizing and thermal management
The G3NB-240B-1 requires the Y92B-N150 heat sink (150 mm × 200 mm extruded aluminum) for continuous operation above 6 A. Without a heat sink, the SSR's load current is limited to 6 A at 40 °C ambient — beyond this, the triac's junction temperature exceeds 125 °C and the device fails. The Y92B-N150 heat sink provides the thermal mass to dissipate the heat generated by the SSR's on-state voltage drop (~1.5 V × 40 A = 60 W of heat at full load).
G3NB-240B-1 vs G3NB-210B-1 vs G3NB-225B-1 vs G3NB-275B-1 vs G3NB-290B-1
The G3NB series is a 5-tier current family for OEM applications: - G3NB-205B-1 = 5 A, 60 A inrush, Y92B-N50 heat sink (small loads, signals) - G3NB-210B-1 = 10 A, 150 A inrush, Y92B-N50 heat sink (already done — small heaters, solenoid valves) - G3NB-220B-1 = 20 A, 220 A inrush, Y92B-N100 heat sink (mid-size heaters) - G3NB-225B-1 = 25 A, 220 A inrush, Y92B-N150 heat sink (mid-size heaters) - G3NB-240B-1 = 40 A, 410 A inrush, Y92B-N150 heat sink (THIS SKU — large heaters, oven bands) - G3NB-275B-1 = 75 A, 800 A inrush, Y92B-P250NF heat sink (extra-large ovens, large process heaters) - G3NB-290B-1.
Key Features
- 40 A load current at 24-220 VAC
- 0.1 to 6 A without heat sink at 40 °C ambient
- Load voltage range: 19 to 286 VAC operating
- Zero-cross switching: critical for heater and transformer loads
- Inrush current: 410 A peak — handles transformer-coupled loads and large heaters
- Control input: DC 5 to 24 VDC, 4-6 mA input current
- Phototriac isolation between input and output
- Operate time: 1 ms max
- SKU: G3NB-240B-1 DC5-24V
- Series: G3NB Solid State Relays (compact OEM-style)
- Voltage: 24 TO 220 VAC
- I/O: 5 I/O
Best-Fit Applications
- Injection-molding barrel heater control — 4-6 × 40 A band heaters on a plastic injection molding machine, each controlled by.
- Food-processing oven heater bank — 4 × 40 A heating elements in a commercial baking oven, each controlled by a.
- Plastic extruder heater zones — 6-8 × 40 A extruder barrel heaters on a plastic extrusion line, each controlled by.
- Packaging heat-seal jaws — 4 × 40 A heat-seal band heaters on a form-fill-seal packaging machine, each controlled by a.
Buying Checklist
- Pick G3NB-240B-1 DC5-24V for 40 A zero-cross AC SSR with heat sink — OEM high-volume heater control, 410 A inrush for transformer-coupled loads
- Pick G3NB-210B-1 DC5-24V for 10 A zero-cross SSR — small heaters, solenoid valves, indicator lights
- Pick G3NB-225B-1 DC5-24V for 25 A zero-cross SSR — mid-size heaters, smaller than G3NB-240B-1
- Pick G3NB-275B-1 DC5-24V for 75 A zero-cross SSR — large process heaters, industrial oven bands
- Pick G3NB-290B-1 DC5-24V for 90 A zero-cross SSR — extra-large industrial process heaters
- Pick G3NA-210B-UTU DC5-24 for 10 A industrial DIN-rail SSR — heavy-industrial long-life applications with Y92B-N100 heat sink
Technical Specifications
| Model | G3NB-240B-1 DC5-24V |
|---|---|
| Series | G3NB Solid State Relays (compact OEM-style) |
| Type | Zero-cross solid-state relay, 40 A, 24-220 VAC, DC 5-24 V control |
| Rated Load Voltage | 24 to 220 VAC |
| Operating Load Voltage Range | 19 to 286 VAC |
| Load Current (with heat sink at 25 °C) | 0.1 to 40 A |
| Load Current (with heat sink at 40 °C) | 0.1 to 40 A (4-6 A at 25 °C without heat sink) |
| Load Current (without heat sink at 40 °C) | 0.1 to 6 A (significant derating) |
| Inrush Current Withstand | 410 A peak (60 Hz, 1 cycle, 1 non-repetitive) |
| Output Device | Phototriac (zero-cross switching) |
| Control Input Voltage | 5 to 24 VDC |
| Control Input Current | 4 to 6 mA (at 5 VDC: 4 mA typical; at 24 VDC: 6 mA typical) |
| Input Terminal | M3.5 screw terminals (2 terminals: +, -) |
| Mounting | Panel mount via two M4 screws (heat sink surface) |
| Dimensions (W × H × D) | Approx 50 × 100 × 50 mm (without heat sink) |
Resources & Downloads
FAQ for G3NB-240B-1 DC5-24V
What heat sink do I need for the G3NB-240B-1 DC5-24V?
The G3NB-240B-1 DC5-24V requires the Y92B-N150 heat sink (150 × 200 mm extruded aluminum) for continuous operation above 6 A. Without a heat sink, the SSR's load current is limited to 6 A at 40 °C ambient — beyond this, the triac's junction temperature exceeds 125 °C and the device fails within minutes to hours.
What's the difference between G3NB-240B-1 and G3NA-210B-UTU?
Both are Omron AC-output zero-cross solid-state relays with DC 5-24 V control input, but they target different applications: G3NB-240B-1 is the cost-optimized OEM-style SSR with screw terminals and 40 A current rating, requiring an external Y92B-N150 heat sink. G3NA-210B-UTU (already done in batch 16) is the higher-spec industrial SSR with 10 A current rating, integrated heat-sink-mounting surface, and built-in surge absorption for the output triac.
Can the G3NB-240B-1 switch DC loads?
No — the G3NB-240B-1 uses a phototriac output device, which is specifically designed for AC load switching. Triacs cannot turn off DC loads because the DC voltage never crosses zero — the triac latches ON and cannot be commutated off. For DC load switching (e.g., DC heaters, DC solenoids, DC motors), use the G3NA-D210B-UTU DC5-24 (already done in batch 16) which uses a MOSFET output instead of phototriac — MOSFETs can switch DC loads cleanly.
What's the inrush current capability of the G3NB-240B-1 DC5-24V?
The G3NB-240B-1 DC5-24V can withstand an inrush current of 410 A peak for 1 AC cycle (60 Hz) before the triac fails. This is sufficient for typical transformer-coupled loads (10-30x steady-state current for the first 1-10 cycles) and large heater banks (10-20x cold-to-hot resistance ratio). For a 5 kW heater at 240 VAC, the steady-state current is ~21 A, and the cold inrush is ~210-420 A — within the G3NB-240B-1's 410 A rating.
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