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3. Key Technical Specifications
| Parameter | Value |
|---|---|
| Product Type | Fan Subassembly (Lüfterzeile) |
| Compatible Rack | S7-400 subrack with 18 slots |
| Supply Voltage | 24 V DC |
| Permissible Voltage Range | 19.2 to 28 V DC (static) |
| Rated Current | 450 mA |
| Starting Current | 0.9 A at 24 V |
| Power Consumption | 12 W (with fan); 1.4 W (without fan) |
| Fan Lifespan | Typ. 70,000 h at 40 °C |
| Dimensions (W × H × D) | 482.5 × 109.5 × 235 mm |
| Weight | Approx. 1.6–2.73 kg |
| Relay Contact Rating | 24 V DC / 200 mA max |
| Status | Product cancelled (discontinued) |
4. Product Introduction
The Siemens 6ES7408-1TA01-0XA0 is a 24 V DC fan subassembly designed for SIMATIC S7-400 subracks with 18 slots. It provides forced-air cooling to maintain proper operating temperatures for the CPU, power supply, and I/O modules in the rack.
This unit mounts directly on the S7-400 rack and includes status signaling via relay contacts. It is used in process and manufacturing plants that require reliable cooling for high-slot-count S7-400 systems. The module is a direct form-fit replacement for existing 18-slot fan assemblies when the original unit fails or reaches end of service life.
5. Troubleshooting Quick Reference
| Symptom | Possible Cause | Relevance to this Part | Quick Check Method | Recommendation |
|---|---|---|---|---|
| Fans not running | Power supply failure or blown fuse | ✅ High | Measure 24 V DC at input terminals; check fuse | Verify power feed and replace fuse if needed |
| High rack temperature / thermal alarms | Fan failure or blocked airflow | ✅ High | Observe fan rotation; check for dust/blockage | Clean or replace fan subassembly |
| No status signal from fan unit | Relay contact fault or wiring issue | ✅ High | Check relay contacts 1–6 with multimeter | Verify wiring and contact continuity |
| Intermittent fan operation | Voltage outside range or aging fans | ✅ Medium | Measure supply voltage under load | Confirm voltage stays within 19.2–28 V |
| Module not detected / no diagnostics | Communication or seating problem | ✅ Medium | Reseat unit; check mechanical mounting | Ensure proper installation per Siemens guidelines |
| Excessive noise or vibration | Worn bearings or imbalance | ✅ High | Listen and feel for abnormal operation | Replace unit; typical fan life is ~70,000 h |
If problems continue after these checks, record voltage readings, photos of the unit and rack, and contact technical support with the serial number and system configuration details.
- 6ES7408-1TA01-0XA0
- 6ES7408-1TA01-0XA0
6. Frequently Asked Questions (FAQ)
Q: What is the 6ES7408-1TA01-0XA0 used for?
A: It is the 24 V DC fan subassembly for SIMATIC S7-400 racks with 18 slots. It provides forced cooling and status signaling for the rack.
Q: Is this part still in production?
A: No. Siemens cancelled the product (discontinued). New surplus and refurbished units remain available on the secondary market, but stock is limited. Confirm compatibility with your exact rack revision before ordering.
Q: Can I replace just one fan or do I need the full subassembly?
A: The unit is supplied and replaced as a complete subassembly. Individual fan replacement is not a standard field procedure and can compromise reliability and warranty.
Q: What voltage does it require?
A: Nominal 24 V DC. Permissible static range is 19.2–28 V DC. Starting current is approximately 0.9 A.
Q: Does it work with 9-slot or other S7-400 racks?
A: No. This specific part number is designed for 18-slot subracks. Using it on a different rack size is not supported.
Q: Why is surplus stock often less expensive than original list price?
A: New Surplus units are unused OEM material that never entered service—typically excess project inventory. They are functionally new but may lack current factory packaging or the original Siemens warranty. Every unit is tested and carries our warranty coverage.
Q: How do you test these fan units before shipping?
A: Each unit undergoes visual inspection, power-up verification at 24 V DC, fan rotation and airflow check, relay contact testing, and a short burn-in run. Test reports are available on request.
