Product Overview
In modern industrial automation, maintaining a continuous and reliable power supply is critical. The ABB SS823 Voter and Over Voltage Protection addresses this need by serving as a control unit in redundant power supply configurations. Designed for high-integrity systems, it connects the outputs from two power supply units, supervises voltage delivery, and generates supervision signals for downstream equipment. This ensures that critical processes remain operational even if one power source fails.
Technical Specifications Breakdown
The SS823 offers several key specifications that define its performance:
- Rated Output Current: 20 A, providing ample capacity for powering control systems.
- Rated Input Power: 500 W, supporting robust power handling.
- Mains/Input Voltage: 1x24 V d.c., suitable for standard industrial DC supplies.
- Maximum Output Current: 35 A (Overload), offering a safety margin for transient conditions.
- Output Over Voltage Protection: < 30 V, safeguarding connected equipment from voltage spikes.
- Heat Dissipation: 24 W at 20 A and 6 W at 5 A, indicating efficient thermal management.
- Supervision Relay: Yes, enabling remote monitoring of output status.
- Load Sharing: Yes, balancing current between redundant supplies.
These parameters make the SS823 ideal for applications where power redundancy and protection are paramount.
Industry Applications
The SS823 is particularly suited for high-integrity systems such as safety instrumented systems (SIS) and emergency shutdown (ESD) networks. In a typical scenario, two SD83x power supplies feed into the SS823, which then provides a clean, supervised output to an AC 800M High Integrity controller and S880 I/O system. This configuration ensures that a single power supply failure does not disrupt critical control functions. The unit's double overvoltage protection on both inputs further enhances system reliability.
Installation & Setup Guidance
Mounting the SS823 is straightforward with its DIN-rail design. Ensure the unit is connected to Protective Earth (PE) for Class I equipment compliance. The voting unit trip levels are factory preset, so no field adjustment is needed. When wiring, connect the outputs from two power supplies to the designated input terminals. The voltage-free contact closes when the green LED illuminates, indicating correct output voltage. For SELV or PELV applications, verify that the upstream power supply meets these standards.
Maintenance & Reliability
The SS823 requires minimal maintenance due to its solid-state design. However, periodic inspection of the green LEDs and supervision relay operation is recommended. The unit is G3 compliant for corrosive atmospheres (ISA-S71.04 G3), making it suitable for harsh environments. With an IP20 protection rating, it should be installed in a clean, dry enclosure. Regular checks of ambient temperature (max 55 °C) and ventilation ensure long-term reliability.
Compatibility & Integration
This voter integrates seamlessly with ABB's AC 800M High Integrity controllers and S880 High Integrity I/O systems. It accepts inputs from any SELV/PELV power supply, such as the SD83x series. The SS823 also features load sharing and supervision relay outputs, making it compatible with standard PLC and DCS monitoring inputs. Its SIL3 certification (per IEC 61508) ensures it meets the highest safety integrity requirements.
Selection Guide & Purchasing Advice
Before purchasing the SS823 (3BSE038226R1), verify that your system requires a redundant power voting unit with double overvoltage protection. Confirm input voltage is 24 V d.c. and that the total load does not exceed 20 A continuous (35 A overload). For applications needing ATEX Zone 2 certification, this model is approved. SpareTechPLC offers this unit with full warranty and support. Contact us to check current lifecycle status and availability.
Frequently Asked Questions
Q: What is the purpose of the double overvoltage protection on the SS823?
A: The double overvoltage protection circuit on both inputs ensures that if one protection stage fails, the backup still safeguards the connected equipment from voltage spikes above 30 V.
Q: Can the SS823 be used with non-ABB power supplies?
A: Yes, as long as the power supply is SELV or PELV rated and provides 24 V d.c. output. The unit is designed to work with any compliant supply.
Q: How do I know if the SS823 is functioning correctly?
A: The front panel green LEDs illuminate when the output voltage is correct. Simultaneously, the voltage-free contact closes, which can be monitored by a PLC or DCS.
Q: What is the maximum ambient temperature for operation?
A: The SS823 can operate in ambient temperatures up to 55 °C. Ensure adequate ventilation to maintain reliability.
Q: Is the SS823 suitable for SIL3 applications?
A: Yes, it is certified for SIL3 according to IEC 61508, making it appropriate for high-integrity safety systems.
