- Model Interpretation and Basic Information
| Item | Details |
| Complete Model | 3RT1024-1BB40 |
| Product Series | Siemens SIRIUS 3RT1 Series (Discontinued, Replacement Model: 3RT2024-1BB40) |
| Structural Specification | 3-pole, Size S0, Screw Termination, IP20 Protection Class |
| Tensione della bobina | DC24V (24 Volt DC) |
| Main Contact Configuration | 3 Normalmente aperto (3NO) |
| Application Category | AC-3 (Three-Phase Motor Load) 12UN, 5.5kW/400V |
- Core Parameters of Thermal Current (Ith)
- Thermal Current of Main Contacts
| Current Type | Rated Value | Applicable Conditions | Remarks |
| AC-1 (Carico resistivo) Thermal Current | 40UN | 690V e, 50/60Hz | Maximum allowable current for long-term operation |
| AC-3 (Carico del motore) Corrente nominale | 12UN | 400V e, 50/60Hz | Corresponding to 5.5kW three-phase motor |
| DC-1 (DC Resistive Load) Thermal Current | 12UN | 24A DC | Long-term operating current for DC circuits |
| DC-3 (DC Motor Load) Corrente nominale | 8UN | 24A DC | Starting and operating current for DC motors |
- Thermal Current of DC24V Coil
| Parametro | Valore | Calculation Basis |
| Rated Coil Power | 5.9W | Siemens official data |
| Coil Thermal Current | 0.246UN | I = P/U = 5.9W/24V |
| Coil Resistance | Approx. 97.5 | R = U/I = 24V/0.246A |
| Coil Pick-Up/Holding Power | 5.9W for both | DC coil has the same pick-up and holding power |
III. Key Technical Characteristics
- Load Adaptation: Suitable for controlling ≤12A resistive load or ≤8A DC motor load in DC24V circuits
- Operating Temperature: -25°C ~ 60°C, adaptable to industrial environments
- Vita meccanica: 3×10⁷ operations, Vita elettrica (AC-3): 1×10⁶ operations
- Insulation Voltage: 690V, reliable electrical isolation performance
- Replacement Models and Compatibility
Preferred Replacement Model: 3RT2024-1BB40 (Siemens SIRIUS 3RT2 Series)
Identical main contact and coil parameters, with an additional 1NO+1NC auxiliary contact
Compatible mounting dimensions for direct replacement
Other Compatible Models:
Schneider: LC1D12BD (DC24V, 12UN, 3NO)
ABB: A12-30-0124VDC (12UN, 3NO, DC24V)
- Note sull'utilizzo
- DC Circuit Application: When controlling DC24V circuits, derate the main contacts for use (≤12A resistive load) and install a surge suppressor (freewheeling diode) to protect the contacts
- Heat Management: Ensure adequate ventilation for the contattore, avoid enclosed installation, and further derate the load when the ambient temperature exceeds 40°C (10% derating for every 10°C rise)
- Protezione della bobina: For the DC24V coil, pay attention to power supply fluctuations (allowable range: 21.6V~26.4V DC) to avoid burnout due to overvoltage
- Metodo di montaggio: Supports 35mm standard DIN rail mounting or panel mounting, with no restriction on mounting direction
Riepilogo
For Siemens 3RT1024-1BB40 in DC24V circuits, the thermal current of the main contacts is 12A (carico resistivo) and the thermal current of the DC24V coil is approximately 0.246A. This model has been discontinued, and it is recommended to use the replacement model 3RT2024-1BB40 as the first choice, which features better performance and an added auxiliary contact function.
Siemens 3RT1024-1BB40 Selection Quick Reference Table (DC24V/Thermal Current Special)
Applicable Scenarios: Procurement Verification / On-Site Installation / Model Replacement / Parameter Review
| Module | Item | Rated Parameter/Core Information | Remarks/Applicable Conditions |
| Basic Information | Product Model | 3RT1024-1BB40 | Siemens SIRIUS 3RT1 Series (Discontinued) |
| Tensione della bobina | DC24V (Direct Current) | Consistent pick-up/holding power | |
| Configurazione dei contatti | 3-pole main contacts (3NO), no auxiliary contacts | IP20 protection, screw termination | |
| Structural Specification | Size S0, 35mm standard DIN rail mounting | No mounting direction restriction, panel/rail mountable | |
| Main Contact Current Parameters | AC-1 (Carico resistivo) Thermal Current | 40A@690V AC/50/60Hz | Maximum allowable current for AC long-term operation |
| AC-3 (Carico del motore) Corrente nominale | 12A@400V AC/50/60Hz (5.5kW three-phase motor) | Rated for AC motor starting/operation | |
| DC-1 (Carico resistivo) Thermal Current | 12A@24V DC | Core parameter for DC24V long-term operation (Key Point) | |
| DC-3 (Carico del motore) Corrente nominale | 8A@24V DC | Adapted for DC24V motor load | |
| DC24V Coil Parameters | Rated Power | 5.9W | Siemens official rating |
| Coil Thermal Current | 0.246UN | Calculation formula: I=P/U=5.9W/24V | |
| Coil Resistance | Approx. 97.5OH | Calculation formula: R=U/I=24V/0.246A | |
| Allowable Voltage Range | 21.6V~26.4V DC (±10%) | Avoid coil burnout from over/undervoltage | |
| Life/Insulation | Vita meccanica | 3×10⁷ operations | Industrial-grade durability |
| AC-3 Electrical Life | 1×10⁶ operations | Adapted for frequent motor start/stop | |
| Insulation Voltage | 690V AC/DC | Reliable electrical isolation performance | |
| Preferred Replacement Model | Modello | 3RT2024-1BB40 (Siemens 3RT2 Series) | Original factory upgraded model, direct compatible replacement |
| Core Compatibility Points | Same main contact/coil/mounting dimensions as 3RT1024-1BB40 | No rewiring cost, direct replacement | |
| Upgrade Points | Added 1NO+1NC auxiliary contacts, improved protection/durability | First choice for cost performance | |
| Cross-Brand Compatible Models | Schneider | LC1D12BD | DC24V, 3NESSUN contatto principale, 12A@400V AC-3 |
| ABB | A12-30-01*24VDC | DC24V, 3NESSUN contatto principale, 12A@400V AC-3 | |
| Installation/Usage Key Points | Installation Requirements | 35mm standard DIN rail, ventilated installation, avoid enclosure | Reduce temperature rise, ensure heat dissipation |
| DC Protection | Install a freewheeling diode on main contacts when controlling DC24V circuits | Suppress surges, prevent contact erosion | |
| Temperature Derating | 10% load current derating for every 10°C rise when ambient temperature >40℃ | per esempio., DC24V resistive load ≤10.8A at 50℃ | |
| Operating Temperature | -25℃ ~ 60℃ | Adapted for industrial high/low temperature environments |
Key Highlighted Points: DC24V resistive load thermal current 12A, coil thermal current 0.246A, preferred replacement model 3RT2024-1BB40
Contattore,interruttore automatico,inverter solare,contatore elettrico,batterie solari


















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