GN84136121 25A SOLID STATE RELAY(USED)
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The GN84136121 is a high-performance Dual-Channel Solid State Relay (SSR) manufactured by Crouzet (part of the GN series).
Unlike the "hockey puck" Crydom SSR discussed earlier, this is a GN Dual model, meaning it contains two independent 25A relays in a single compact housing. This is incredibly efficient for switching both lines of a 220V AC system or controlling two separate loads.
Load Current:25A per channel (with a proper heat sink).
Load Voltage:24V to 600V AC.
Control Voltage:4V to 32V DC.
Switching Type:Zero-Cross Switching. This reduces electrical noise and inrush current by waiting for the AC voltage to hit zero before turning on.
Terminal Type: IP20-rated "touch-safe" screw terminals (elevated for safety).
In a 220VAC Inverter system, safety and space are the biggest concerns. The GN84136121 offers a professional solution:
In a pure sine wave inverter, it is best practice to disconnect both the Live (L) and Neutral (N) wires when the system is off. Since this has two channels, one GN84136121 can switch both lines simultaneously using a single control signal.
Instead of mounting two large relays, this dual-channel unit fits into a standard SSR footprint. This is perfect for the compact enclosures used in the EE55 2kW project.
Since it is rated up to $600\text{V}$, it is highly resistant to the "voltage spikes" that can occur on an AC line, making it much more durable than standard 240V-rated relays.
Like all SSRs, the GN84136121 generates heat through internal resistance.
Heat Calculation: At 25A on both channels, the unit can generate approximately 1.2W per Amp. 25A X 1.2 X 2 channels = mathbf60W of heat.
The Rule: You must mount this on a finned aluminum heat sink. For 25A loads, active cooling (a fan) blowing over the heat sink is highly recommended to prevent the internal SCRs from overheating and failing.
Comparison: Single vs. Dual SSR
| Feature | Crydom D4850C (Single) | Crouzet GN84136121 (Dual) |
| Max Current | 50A (one line) | 25A per line (two lines) |
| Circuit Type | Single Pole | Double Pole (L + N) |
| Terminals | Exposed Screws | Touch-Safe (IP20) |
| Best Use | Single high-power load | Inverter Output / AC Transfer |
Control Input: You can tie the positive control inputs of both channels together so that one 12V or 5V signal from your EGS002 board switches both channels at once.
Mounting: If you are mounting this inside an inverter case, ensure the back of the SSR is perfectly flat against the heat sink and use a thin layer of thermal grease.