Description:
The 1N1346 is an ABB / former Westinghouse / International Rectifier heritage standard-recovery silicon rectifier diode housed in a threaded stud-mount package (typically DO-4 / DO-5 / DO-203AB style). Rated at 12 A average forward current and 600 V peak reverse voltage, it is designed for general-purpose AC-to-DC rectification, free-wheeling, DC link blocking, and snubber diode duties in industrial drive power sections, welding machines, battery chargers, and vintage control-circuit power supplies where fast-recovery (FRD) characteristics are not required.h2 Application Scenarios:A steel service center still operating a 1980s vintage DC drive-controlled bar shear was experiencing erratic DC bus regulation and occasional fuse blowing on the three-phase bridge rectifier feeding the armature circuit. Visual inspection revealed one of the six original stud-mounted rectifiers had cracked and the anode lead had oxidized. The OEM part cross-referenced to the 1N1346. The maintenance electrician removed the faulty diode—undoing the 10-32 stud nut and two ring-terminal screws—cleaned the mating surfaces with fine emery cloth, applied a thin layer of thermal compound, torqued the new 1N1346 to spec, and reconnected the leads. The drive powered up cleanly; DC bus ripple returned to within original design limits and the intermittent overcurrent trips ceased. The plant’s drive specialist commented that having the correct 1N1346 standard-recovery diode on the shelf “saved a day of hunting for obsolete parts and kept the shear in production during peak shipping season.” This is the classic role of the 1N1346: an unsung but essential component whose correct specification—standard (not fast) recovery, appropriate VRRM, and stud-mount ruggedness—is critical when replacing originals in legacy power electronics.h2
Parameter:
| Main Parameters | Value/Description |
|---|---|
| Product Model | 1N1346 (also cross-listed as 1N1346A, JAN1N1346 depending on screening) |
| Manufacturer | ABB (heritage Westinghouse / IR / SEMIKRON cross-reference) |
| Product Category | Standard Recovery Silicon Rectifier Diode (Stud Mount) |
| Average Forward Current (IF(AV)) | 12 A @ TC= 55 °C (case temp), derated per heatsink |
| Peak Reverse Repetitive Voltage (VRRM) | 600 V |
| Forward Voltage Drop (VF) | ≤ 1.1 – 1.3 V @ 12 A (typical for silicon standard recovery) |
| Reverse Leakage Current (IR) | ≤ 1 mA @ VRRM, 25 °C |
| Non-Repetitive Surge (IFSM) | 250 – 300 A (1 cycle, 60 Hz sine) |
| Recovery Time (trr) | Standard recovery (~ 3 – 5 µs typical; NOT a fast-recovery diode) |
| Package Style | DO-5 / DO-203AB — threaded stud (¼–28 UNF typical) + two solder / pressure tabs or axial leads per variant |
| Cathode / Anode Identification | Stud = Cathode (on most 1N1346; stud = Anode on “R” variants — verify marking) |
| Operating Junction Temp. | -65 °C to +175 °C |
| Mounting Torque | 8 – 12 in-lb (0.9 – 1.4 N·m) on stud nut; use thermal grease for heatsink mating |
| Qualification / Screening | Commercial / JAN / JANTX available per vintage batch |
| Key Note | Match polarity (stud cathode vs. stud anode) to the removed unit before installation |
h2 Technical Principles and Innovative Values:
- Innovation Point 1 — Robust Diffusion-Junction Silicon Design for High Surge Withstand. The 1N1346 employs a diffused p-n junction optimized for standard-recovery rectification rather than fast switching, giving it excellent tolerance to high non-repetitive surge currents (up to 250 A+ for a half-cycle). This makes it ideal for line-frequency bridge rectifiers where momentary inrush from capacitive DC-link charging or transformer magnetizing current would destroy a smaller signal diode.
- Innovation Point 2 — Threaded Stud Mounting for Low Thermal & Electrical Resistance. Unlike press-fit or surface-mount diodes, the 1N1346 mounts via a ¼–28 UNF threaded stud directly into a tapped hole or through-bolted with nut on a machined heatsink. Properly torqued with thermal compound, this provides a low-ohmic path for both heat (to the sink) and return current (through the stud), ensuring the diode operates within its 12 A rating even in warm cabinet environments.
- Innovation Point 3 — MIL-Spec Heritage & Cross-Industry Interchangeability. Originally qualified to MIL-SPEC (JAN / JANTX classes), the 1N1346 remains backward-compatible with countless legacy drive, welder, and plating-rectifier designs. It directly replaces 1N1190, 1N1202, and many OEM-specific stud diodes of equivalent VRRM/ IF, making it a versatile single-part inventory item for plants maintaining mixed-vintage equipment.
h2 Application Cases and Industry Value:Case — Plating Shop 3-Phase Bridge Rectifier Overhaul: An electroplating line used a 500 A 12 V DC rectifier built from six stud-mounted diodes in a full-wave bridge. Two diodes failed after 15 years of continuous duty. The original OEM part was discontinued; cross-reference pointed to the ABB 1N1346 (12 A rating sufficient for the control / pilot supply bridge of the regulator, not the main 500 A stack—those used larger 1N3208-class units). The control bridge was rebuilt with six new 1N1346 diodes, restoring the automatic voltage-regulation reference circuit. The plating shop supervisor noted that “the reference was rock-steady again—no more wandering bath voltage,” and the 12-per-diode spend prevented a 4,000 new rectifier controller purchase.
