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Siemens SIRIUS series single-function electronic on-delay timing relay with 2 changeover contacts, wide-range AC/DC 12–240V supply, and timing range from 0.05 seconds to 100 hours. Suitable for applications requiring precise time delay control in industrial automation control systems.
1 Model Breakdown & Product Overview
| Model Segment | Meaning |
| 3RP | Product identifier for Siemens SIRIUS timing relays |
| 25 | Single‑function timing relay series (3RP25 = single‑function; 3RP20 = multi‑function) |
| 25 | Product sub‑series number |
| 1 | Function code (1 = on‑delay) |
| BW | Contact and voltage combination code (2 changeover contacts, AC/DC 12–240V) |
| 30 | Terminal type code (30 = screw terminals) |
Features
Single-function design, simple operation, high reliability
Wide-range universal power supply compatible with various systems
7 adjustable timing ranges covering extensive delay requirements (0.05 s ~ 100 h)
2 independent changeover contacts (DPDT) for versatile control
Rail mounting for space-saving installation in control cabinets
2 Key Technical Parameters
| Parameter | Specification |
| Basic Function | Electronic on‑delay timing relay |
| Contact Configuration | 2 changeover contacts (2CO / DPDT) |
| Rated Control Supply | AC/DC 12–240V (AC 50/60 Hz), wide‑voltage design |
| Timing Range | 7 adjustable ranges: 0.05s / 0.5s / 5s / 50s / 5min / 30min / 100h |
| Setting Accuracy | ±5% of full scale value |
| Repeat Accuracy | Approx. ±1% |
| Reset Time | 250 ms |
| Rated Operational Current | AC‑15: 230V / 3A; DC‑13: 24V / 0.3A |
| Thermal Current | 5 A |
| Mechanical Life | Approx. 10,000,000 operating cycles |
| Electrical Life | Approx. 100,000 cycles at AC‑15 230V |
| Mounting | DIN rail mounting (compliant with EN 60715) |
| Protection Class | IP20 (front) |
| Operating Temperature | –25 °C to +60 °C |
| Dimensions (H×W×D) | 100 mm × 22.5 mm × 90 mm |
3 Installation & Connection
- Mounting: Standard 35 mm DIN rail (22.5 mm width, space-saving)
- Terminals: Screw terminals for reliable connection and easy wiring
- Indicator: Integrated LED status indicator for power and timing status
- Wiring Diagram:
A1/A2: Control power supply input
11-12-14: 1st changeover contact (11-12 = NC, 11-14 = NO)
21-22-24: 2nd changeover contact (21-22 = NC, 21-24 = NO)
4 Applications
Industrial Automation
Star-delta starting delay control for motors
Sequential start/stop of conveyor systems
Preheating delay control for heating systems
Delay protection control for pump sets
Building & HVAC
Ventilation system delay control
Time-delay switching for lighting systems
Interlock control in fire protection systems
Other Applications
Safety door time-delay interlocking
Equipment maintenance interval signaling
Sequence control in process systems
5 Comparison of Models in the Same Series
Main differences among 3RP25 single-function timing relays:
| Model | Function | Contacts | Voltage | Terminal |
| 3RP2525‑1BW30 | On‑delay | 2CO | AC/DC 12–240V | Screw |
| 3RP2525‑1AW30 | On‑delay | 2CO | AC 24–240V | Screw |
| 3RP2525‑1BW40 | On‑delay | 2CO | AC/DC 12–240V | Spring |
| 3RP2525‑2BW30 | Off‑delay | 2CO | AC/DC 12–240V | Screw |
| 3RP2525‑3BW30 | Interval delay | 2CO | AC/DC 12–240V | Screw |
6 Replacement & Compatibility
- Upgrade Replacement
The 3RP25 series is the upgraded successor to the 3RP15 series. Functionally compatible and identical in size, it can be directly substituted.
- Cross-Brand Replacements
Omron H3CR series single-function timing relays
Schneider RE7 series timing relays
ABB CT series timing relays
7 Key Selection Criteria
- Confirm function: on-delay (this model), off-delay, or interval delay
- Verify contact configuration: 2 changeover contacts to meet control circuit requirements
- Check voltage compatibility: control supply within AC/DC 12–240V range
- Ensure timing range covers required delay (0.05 s ~ 100 h)
- Confirm DIN rail mounting requirement
- Select terminal type: screw or spring (this model uses screw terminals)
8 Notes
- Allow sufficient heat dissipation space during installation; avoid direct contact with heat-generating components
- Disconnect power before wiring to prevent electric shock
- Select appropriate timing range according to actual needs to avoid misoperation
- No built-in overvoltage protection; surge protection is recommended on the power supply side
Complete List of Siemens 3RP Series Timing Relays
& Cross-Brand Ordering Cross-Reference
1 Overview of the 3RP Series
The Siemens 3RP series consists of electronic timing relays under the SIRIUS brand, divided into three main lines:
3RP25 (current mainstream, compact, 17.5 / 22.5 mm width)
3RP20 (contactor-style design, 45 mm width)
3RP15 (discontinued, replaced by 3RP25, 22.5 mm width)
2 Complete Model List-3RP25 Series (Mainstream)
2.1 Multi-Function Timing Relays (13–27 functions)
| Width | Prefix | Contacts | Voltage Code | Terminal Type | Typical Models | Features |
| 17.5 mm | 3RP2505 | 1CO | 1AW: AC 24–240V | 30: Screw | 3RP2505‑1BW30 | 13 functions, 7 timing ranges (0.05s~100h), wide voltage |
| 1BW: AC/DC 12–240V | 40: Spring | 3RP2505‑2BW40 | ||||
| 2AW: AC 24–240V (spring) | ||||||
| 2BW: AC/DC 12–240V (spring) | ||||||
| 22.5 mm | 3RP2505 | 2CO | 1BW: AC/DC 12–240V | 30: Screw | 3RP2505‑1BW30 | 13 functions, 7 timing ranges, 2 independent changeover contacts |
| 2BW: AC/DC 12–240V (spring) | 40: Spring | 3RP2505‑2BW40 |
2.2 Single-Function Timing Relays (On-Delay / Off-Delay / Interval)
| Width | Prefix | Function Code | Contacts | Voltage Code | Typical Models | Timing Range |
| 17.5 mm | 3RP2512 / 3RP2525 | 1: On‑delay | 1CO / 2CO | 1AW: AC 24–240V | 3RP2525‑1BW30 | 7 ranges (0.05s~100h), single‑function, easy operation |
| 2: Off‑delay | 1BW: AC/DC 12–240V | 3RP2525‑2BW40 | ||||
| 3: Interval | 2AW: AC 24–240V (spring) | 3RP2512‑1AW30 | ||||
| 2BW: AC/DC 12–240V (spring) |
2.3 Special-Function Timing Relays
| Function | Prefix | Contacts | Typical Models | Application |
| Star‑delta starting | 3RP2574 | 1NO delayed + 1NO instantaneous | 3RP2574‑1NW30 | Motor star‑delta switching, fixed 1s~20s range |
| 3RP2574‑2NW40 | ||||
| Pulse output | 3RP2560 | 1NO delayed | 3RP2560‑1SW30 | Pulse generation, cyclic timing control |
| 3RP2560‑2SW40 | ||||
| 2‑wire control | 3RP2527 | 1CO | 3RP2527‑1EW30 | Replacement for conventional electromechanical timers, low power |
3 Model List-3RP20 Series (Contactor Design, 45 mm)
| Prefix | Function | Contacts | Typical Models | Features |
| 3RP2005 | Multi‑function (8 functions) | 1CO / 2CO | 3RP2005‑1AQ30 | Contactor housing, 45 mm width, for large control cabinets |
| 3RP2005‑2AQ30 | ||||
| 3RP2025 | On‑delay | 1CO / 2CO | 3RP2025‑1AQ30 | Single‑function, 15 timing steps, AC 24–240V |
| 3RP2025‑2AQ30 | ||||
| 3RP2032 | Off‑delay | 1CO / 2CO | 3RP2032‑1AQ30 | Single‑function, for equipment shutdown delay control |
4 Model List-3RP15 Series (Discontinued, Replaced by 3RP25)
| Prefix | Function | Replacement 3RP25 Model | Remarks |
| 3RP1505 | Multi‑function (8) | 3RP2505 | 22.5 mm width, discontinued |
| 3RP1525 | On‑delay | 3RP2525 | 22.5 mm width, 15 timing steps, widely used |
| 3RP1532 | Off‑delay | 3RP2532 | 22.5 mm width, for shutdown delay |
| 3RP1574 | Star‑delta | 3RP2574 | 22.5 mm width, motor control |
| 3RP1560 | Pulse output | 3RP2560 | 22.5 mm width, cyclic control |
5 Cross-Brand Ordering Cross-Reference
| Siemens Model | Function | Omron Equivalent | Schneider Equivalent | ABB Equivalent | Remarks |
| 3RP2525‑1BW30 | On‑delay | H3CR‑A8 AC/DC 100–240V | RE7RA11BU | CT‑MFE 24–240V AC/DC | Single‑function, 2CO, wide voltage |
| (On‑delay, 2CO, AC/DC 12–240V) | H3CR‑F8 AC 100–240V | RE7RA11MW | |||
| 3RP2505‑1BW30 | Multi (13 functions) | H3CR‑P8 AC/DC 100–240V | RE7RM11MW | CT‑MFE/8 24–240V AC/DC | 13 functions, 7 timing ranges |
| (Multi‑function, 1CO, AC/DC 12–240V) | H3CR‑V8 AC/DC 12–240V | RE7RM21MW | |||
| 3RP2574‑1NW30 | Star‑delta switching | H3CR‑S8 AC 100–240V | RE7RK11MW | CT‑MFE/ST 24–240V | Special function, 1s~20s fixed range |
| (Star‑delta) | |||||
| 3RP2560‑1SW30 | Cyclic timing | H3CR‑T8 AC 100–240V | RE7RP11MW | CT‑MFE/P 24–240V | Pulse generation for intermittent operation |
| (Pulse output) | |||||
| 3RP2527‑1EW30 | 2‑wire control | H3CR‑G8 AC 100–240V | RE7RL11MW | CT‑MFE/2W 24–240V | Low‑power replacement for electromechanical timers |
| (2‑wire) |
6 3RP15 → 3RP25 Replacement Table (Official Recommendation)
| Original 3RP15 Model | Replacement 3RP25 Model | Compatibility |
| 3RP1525‑1BW30 | 3RP2525‑1BW30 | Fully compatible, same dimensions, identical function |
| 3RP1505‑1BW30 | 3RP2505‑1BW30 | Upgraded functions (8 → 13), same timing range |
| 3RP1574‑1NQ30 | 3RP2574‑1NW30 | Star‑delta function retained, wide voltage improved |
| 3RP1560‑1SP30 | 3RP2560‑1SW30 | Pulse function unchanged, terminal layout identical |
7 Key Selection Parameter Comparison
| Parameter | 3RP25 Series | Omron H3CR Series | Schneider RE7 Series | ABB CT Series |
| Voltage Range | AC/DC 12–240V | AC 100–240V / DC 12–48V | AC/DC 24–240V | AC/DC 24–240V |
| Timing Range | 0.05s~100h (7 steps) | 0.05s~100h (multi‑range) | 0.05s~100h (multi‑range) | 0.05s~100h (multi‑range) |
| Number of Functions | 13–27 | 8–16 | 10–20 | 8–16 |
| Contact Config | 1CO / 2CO / 1NO+1NC | 1CO / 2CO | 1CO / 2CO | 1CO / 2CO |
| Mounting Width | 17.5 / 22.5 mm | 22.5 mm | 22.5 mm | 22.5 mm |
| Terminal Type | Screw / Spring | Screw / Spring | Screw / Spring | Screw / Spring |
8 Ordering & Replacement Notes
- 3RP15 series is discontinued; prefer 3RP25 as a drop-in replacement with better performance.
- Voltage matching: 3RP25 offers AC-only (1AW) and AC/DC universal (1BW) versions; confirm system voltage when ordering.
- Terminal selection: Screw terminals (suffix 30) for low-vibration environments; spring terminals (suffix 40) for fast mass wiring.
- Cross-brand substitution: Direct replacement possible if function and contacts match, but note:
Timing range setting methods may differ
Terminal arrangement may vary
Some brands may require additional accessories
