Siemens 3RF2120-1AA04 SIRIUS 3RF2 Solid-State Relay

The Siemens 3RF2120-1AA04 is a single-phase SIRIUS 3RF2 solid-state relay designed for wear-free, noiseless switching of resistive and inductive AC loads. Rated at 20 A (AC-51) with a 48–460 V AC operating voltage range, it is controlled by a 15–24 V DC signal and uses screw terminals for main circuit connections.

Unlike electromechanical relays, this solid-state device has no moving parts, making it ideal for high-switching-frequency applications and noise-sensitive environments. The compact 22.5 mm width saves valuable space, and the unit can be expanded with standardized 3RF29 function modules for load monitoring, power regulation, or terminal covers.

  • Item nº :

    3RF2120-1AA04
  • Pedido (MOQ) :

    1
  • Pagamento :

    EXW
  • Origem do produto :

    Germany
  • Porto de embarque :

    Wuhan, Hubei, China
  • Tempo de espera :

    3-5 days
  • Peso :

    0.076kg
  • Overview

    3RF2120-1AA04 SIMATIC PLC Module

    New in stock     

    Origin from Germany

    Payment Method: TT.Western Union

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    Recommended Models & Related Products

     
     
    Part Number Description Key Difference
    3RF2120-1AA04 20 A, 48–460 V AC, 15–24 V DC control (this item) Standard screw terminal variant
    3RF2120-1AA24 20 A, 48–460 V AC, 110–230 V AC control AC control voltage variant
    3RF2120-1BA04 20 A, 48–460 V AC, instantaneous switching Non-zero-point switching variant
    3RF2150-1AA04 50 A, 48–460 V AC, 15–24 V DC control Higher current rating
    3RF2920-0HA16 Load monitoring module Optional function module
    Heatsink Required for full 20 A rating Consult datasheet for sizing

    Important: The 20 A rating is the performance capacity of the solid-state relay. The actual permitted rated operational current depends on the connection method, heatsink, and cooling conditions. A suitable heatsink is required to achieve the full 20 A rating. The minimum load current is 100 mA—loads drawing less than this may not switch reliably .

    What's Included

    • 1 × Siemens 3RF2120-1AA04 SIRIUS 3RF2 Solid-State Relay

    Note: Heatsink, function modules, and terminal covers are sold separately.

    Why Buy From Us?

    • In Stock – Ready to ship immediately

    • Genuine Siemens Product – Factory original SIRIUS component, Active Product status

    • Warranty Included – Purchase with confidence

    • Technical Support – Application and heatsink sizing assistance available

    Frequently Asked Questions (FAQ)

    Q1: What is the Siemens 3RF2120-1AA04?

    It is a single-phase SIRIUS 3RF2 solid-state relay with a 20 A rating, 48–460 V AC operating voltage, and 15–24 V DC control signal. It uses zero-point switching and screw terminals for wear-free, noiseless load switching .

    Q2: Does this device require a heatsink?

    Yes. The 20 A rating is the performance capacity. The actual permitted operational current depends on the heatsink and cooling conditions. A suitable heatsink must be used to achieve the full rating. Without adequate cooling, the permissible current is significantly lower .

    Q3: What is zero-point switching?

    Zero-point switching means the device turns on when the AC voltage crosses zero. This minimizes inrush current and electrical noise, extending the life of resistive loads such as heaters .

    Q4: What is the control voltage for this variant?

    The 1AA04 variant uses a 15–24 V DC control signal. For an AC control variant, see the 1AA24 model .

    Q5: What is the minimum load current?

    The minimum load current is 100 mA. Loads drawing less than this may not switch reliably .

    Q6: Can I use this for inductive loads?

    Yes. The device is designed for switching resistive and inductive loads, such as valves and solenoids. The zero-point switching helps reduce stress on inductive loads .

    Q7: What is the power loss at rated current?

    The power loss is 28.6 W at the rated current in hot operating condition. This heat must be dissipated by the heatsink .

    Q8: What are the dimensions and weight?

    Dimensions are 22.5 × 85 × 48 mm (W × H × D). Net weight is 0.076 kg .

    Q9: What is the country of origin?

    Germany (DE) .

    Q10: What should I verify before ordering?

    Always verify the exact part number (3RF2120-1AA04 for 15–24 V DC control), confirm your load current and voltage are within the 20 A / 48–460 V AC range, ensure you have a suitable heatsink for your required current, and check whether you need the AC control variant (1AA24) or instantaneous switching variant (1BA04) for your application.

     
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