ABB NF93A-2 HESG440280R2 HESG323662R1/HESG216665/K Network Filter / Coupling Module
ABB NF93A-2 (HESG440280R2) is a specialized Network / Filter Module (often referred to as a “Mains Filter” or “Coupling Module”)
belonging to the ABB Procontrol P13 and Master control systems.
The complex string of part numbers (HESG323662R1 / HESG216665/K) refers to the specific sub-assemblies and hardware revisions of the internal PCB components.
1. Introduction
The NF93A-2 is primarily a signal conditioning and noise suppression module.
Its role is to protect the sensitive internal system bus and electronic components of the Procontrol P13 rack from electromagnetic interference (EMI),
voltage spikes, and high-frequency noise originating from the power grid or field wiring.
It acts as a “buffer” that ensures the integrity of data and power distribution within the subrack.
2. Technical Parameter Table
| Parameter | Specification |
| Model Number | NF93A-2 |
| Primary Part Number | HESG440280R2 |
| Sub-Assembly Nos. | HESG323662R1 / HESG216665/K |
| Module Type | Network Filter / Coupling Module |
| Nominal Voltage | 24 V DC / 48 V DC (System Dependent) |
| Current Rating | Designed for full subrack load (Up to 10A filtering) |
| Frequency Range | DC up to high-frequency EMI suppression |
| Operating Temp | 0°C to +60°C |
| Form Factor | Eurocard Plug-in (Standard P13 width) |
| Isolation | High galvanic isolation for noise decoupling |
3. Related Models
NF91 / NF92: Earlier versions with lower current or filtering capacities.
500PSM03: The power supply module that often feeds through the NF93A-2.
IW93-2: The analog interface module often found in the same rack.
70PR05: The central processor module that relies on the clean power provided by the NF series.
4. Product Advantages and Features
Advanced EMI Suppression: Effectively filters out “noise” from heavy industrial equipment (motors, welders) that could otherwise cause data corruption.
Voltage Stabilization: Helps smooth out minor fluctuations in the 24V DC logic supply.
Hardware Robustness: Built to military-grade standards (common for the HESG series), designed to run for decades without degradation.
Passive Reliability: Because many NF modules are largely passive or use high-durability components, they have an extremely high MTBF (Mean Time Between Failures).
System Protection: In the event of an external short circuit or surge, the NF93A-2 acts as a sacrificial barrier to protect more expensive processor modules.
5. Application Cases
Power Plant Control: Protecting the P13 bus in thermal and nuclear plants where large switchgear operations generate significant electrical noise.
Steel Mills: Stabilizing logic power near massive high-frequency induction furnaces.
Marine Systems: Used in shipboard automation where the localized power grid (generators) can be “dirty” or unstable.
Retrofit Projects: Installed when legacy P13 systems are expanded and require additional noise filtering for new long-distance I/O runs.
NF93A-2 HESG440280R2
6. Installation and Maintenance
Installation:
Slot Priority: Typically installed in the first slot or a dedicated “filtering” slot immediately adjacent to the Power Supply Module (PSM).
Grounding: Ensure the rack’s earthing bar is connected to the NF93A-2’s front panel or backplane ground to allow noise to drain to the earth.
Maintenance:
Visual Inspection: Check for heat-induced discoloration on the HESG216665/K board, as filtering modules can dissipate heat while suppressing spikes.
Connector Cleaning: Every 5 years, it is recommended to clean the gold-plated edge connectors with an approved electronic cleaner to maintain low-resistance contact.
Replacement Strategy: Since this module is critical for the “health” of the rack, a failure often looks like intermittent “Bus Errors” across multiple other modules. If the rack is acting erratically, the NF93A-2 is a primary suspect for testing.