Description
GE 12HFA51A42H Multicontact Auxiliary Relay
The GE 12HFA51A42H is an HFA Series multicontact auxiliary relay from General Electric. Available documentation and equipment catalogs identify it as a 125 VDC electromechanical auxiliary relay intended for applications where multiple auxiliary switching functions are required simultaneously.
| Specification | Details |
|---|---|
| Brand | GE (General Electric) |
| Part Number | 12HFA51A42H |
| Series / Family | HFA |
| Product Type | Multicontact Auxiliary Relay |
| Relay Technology | Electromechanical, hinged-armature |
| Coil Voltage | 125 VDC |
| Reset Type | Self-reset / instantaneous dropout |
| Contact Configuration | 6 electrically separate contact circuits |
| Connection Style | Front-connected version; suffix H corresponds to surface mounting, front connection |
| Mounting | Surface mount for the front-connected configuration |
| IEEE Device | 94x |
| Instruction Book | GEH-2024 / GEH-2024F references |
| Typical Application | Auxiliary switching, protection, signaling, interlocking and control circuits |
| Approx. Unit Weight | 6.59 lb (2.99 kg), depending on source and configuration |
| Lifecycle | Listed as discontinued by manufacturer by current secondary-market sources |
GE 12HFA51A42H
Product Overview
The 12HFA51A42H is part of GE’s HFA multicontact auxiliary relay family. The HFA51 design provides six electrically separate contact circuits, allowing one relay to perform several auxiliary switching operations at the same time. The contacts can be used for either circuit-opening or circuit-closing functions.
The A42H configuration is associated with a 125 VDC coil, while the final H designation is used for the front-connected, surface-mounted arrangement described in GE’s historical relay documentation.
Application
Typical applications for this relay include:
- Power-system control and protection panels
- Auxiliary trip and control circuits
- Hardwired interlocking logic
- Status and signaling circuits
- Legacy GE control and protection equipment
Historical GE documentation shows the HFA family was designed to perform multiple auxiliary functions simultaneously, including arrangements where several relays could be combined when more than six circuits were required.
Replacement and Procurement Notes
For a replacement purchase, the coil voltage, contact arrangement, mounting/connection style, and reset configuration should be matched against the installed relay. Do not substitute another HFA catalog number solely because it belongs to the same family.
The suffix is particularly important. GE’s historical ordering information distinguishes front-connected and back-connected arrangements, and specifically gives 12HFA51A42H as an example of the front-connected surface-mount configuration.
The exact operating/contact ratings, terminal arrangement, and mechanical dimensions should be confirmed against the applicable GEH-2024 documentation for the specific configuration before installation.
Lifecycle Risk
Current secondary-market listings identify 12HFA51A42H as discontinued by the manufacturer, while other industrial material catalogs continue to list the part as a legacy GE HFA auxiliary relay.
For plants with installed HFA relay panels, maintaining a controlled spare inventory can reduce replacement risk associated with aging electromechanical equipment and declining availability.
FAQ
What is GE 12HFA51A42H?
It is a GE HFA Series multicontact auxiliary relay with a 125 VDC coil and six electrically separate contact circuits.
Is 12HFA51A42H a PLC or electronic module?
No. It is an electromechanical auxiliary relay, not a programmable controller or solid-state I/O module.
What voltage does the relay use?
The available catalog information identifies the coil voltage as 125 VDC.
How many contact circuits are provided?
The HFA51 configuration provides six electrically separate contact circuits.
What does the final “H” mean?
GE’s historical relay documentation uses the H suffix for the front-connected, surface-mount configuration.
Is it obsolete?
Secondary-market sources currently list it as discontinued by the manufacturer. The exact OEM discontinuation date was not established from the sources reviewed.
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