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This Siemens power supply provides stable DC power for S5 automation systems. The Siemens 6ES5988-3LB21 converts AC mains voltage into regulated DC output. Its robust design ensures reliable operation under fluctuating line conditions. This unit supplies power to the rack’s backplane and connected modules. The Siemens 6ES5988-3LB21 includes comprehensive protection features for system safety.
Physical Dimensions and Mounting Details
The power supply measures 232 mm in height and 25 mm in width. Its overall depth reaches 160 mm including the front connector. This unit weighs approximately 0.8 kilograms for stable installation. The housing features a rugged metal casing with ventilation slots. The Siemens 6ES5988-3LB21 plugs directly into the S5 rack’s designated slot. A 48-pin backplane connector transfers power to the rack’s bus.
Input and Output Specifications
This power supply accepts 120 V AC or 230 V AC input voltages. The input frequency range covers 47 Hz to 63 Hz for global compatibility. The output provides 5 V DC at 10 A for logic circuits. A separate 24 V DC output delivers 1 A for relay and field circuits. The Siemens 6ES5988-3LB21 offers a total output power of 70 W. Line regulation stays within ±0.1% for stable system operation. Load regulation remains within ±0.5% under varying load conditions.
Protection and Diagnostic Features
This power supply includes overvoltage protection for all output rails. Short-circuit protection automatically limits output current during faults. Thermal protection shuts down the unit during excessive temperature conditions. The Siemens 6ES5988-3LB21 features an integrated 2200 µF capacitor for energy storage. This capacitor provides hold-up time of approximately 20 milliseconds. A front panel LED indicates the output status and fault conditions.
Detailed Specification Table
| Parameter | Specification |
|---|---|
| Dimensions (H x W x D) | 232 mm x 25 mm x 160 mm |
| Weight | Approx. 0.8 kg |
| Input Voltage | 120 V AC or 230 V AC (selectable) |
| Input Frequency | 47 Hz to 63 Hz |
| 5 V DC Output | 10 A |
| 24 V DC Output | 1 A |
| Total Output Power | 70 W |
| Line Regulation | ±0.1% |
| Load Regulation | ±0.5% |
| Hold-up Capacitance | 2200 µF |
| Hold-up Time | Approx. 20 ms |
| Efficiency | 85% (typical) |
| Operating Temperature | 0°C to 60°C |
Installation and Commissioning Guidelines
Insert this power supply into the far-left slot of the S5 rack. Connect the AC mains to the designated terminal block securely. Select the correct input voltage using the selector switch before power-on. The Siemens 6ES5988-3LB21 operates effectively between 0°C and 60°C. Ensure adequate airflow around the unit for proper heat dissipation. Verify the output voltage using a multimeter after initial power-up. Monitor the LED indicator for normal operation status. Replace the unit immediately if the fault LED remains illuminated.