Description
Key Technical Specifications
| Parameter | Specification |
|---|---|
| Manufacturer | Reliance Electric / legacy Rockwell Automation |
| Part Number | 0-54341-21 |
| Product Type | DC Coil Driver / Contactor Driver |
| Nominal Coil Voltage | 74 VDC |
| Compatible Contactor | 417690-4R |
| Coil Type | Low-resistance coil |
| Coil Resistance | Approximately 76 Ω |
| Primary Function | Contactor coil drive |
| Replacement Reference | 23P-DC-CLDRV-3 |
| Lifecycle | Obsolete |
| Application | Legacy DC drive equipment |
Rockwell’s installation documentation explicitly states that 23P-DC-CLDRV-3 replaces obsolete O-54341-21 and drives the 417690-4R “low res coil”, specified at 76 Ω and 74 VDC.
A separate Reliance spare-parts listing identifies the broader 0-54341 family as a rectifier-related PCB family, including variants for 1200 A and 2500 A applications. That makes the exact -21 suffix particularly important; it should not be confused with the base 0-54341 board or other suffixes.
Application Scenarios & Pain Points
A contactor that does not pull in can waste hours of troubleshooting if the coil driver is overlooked. Before condemning the main drive controller, verify whether the driver is actually delivering the correct coil voltage and whether the contactor coil itself is healthy.
Typical Applications
- Legacy DC Drive Contactor Control: The 0-54341-21 was designed for controlling the specified contactor coil rather than serving as a general PLC output module.
- 417690-4R Contactor Systems: The documented application is specifically the 417690-4R low-resistance coil, rated at approximately 76 Ω.
- High-Power Drive Cabinets: Contactor-driver circuitry is commonly found around the power-input, armature, field, or related switching sections of older DC drive equipment.
- Legacy Equipment Repair: Particularly useful when maintaining an existing installation where the original contactor and control wiring are still serviceable.
Field Case:
A contactor that chatters deserves immediate attention. Measure the coil voltage while commanding the contactor, then check the coil resistance with power removed. If the coil is around 76 Ω and the driver cannot produce the expected 74 VDC command, the driver becomes a strong suspect. Do not keep cycling the contactor while the driver is unstable; the resulting heat can damage both the coil and switching components.
0-54341-21
Related Products
- Reliance Electric 0-54341 — Base Reliance Electric PCB designation associated with rectifier hardware. It is not automatically equivalent to the 0-54341-21 coil-driver configuration.
- Reliance Electric 0-54341-1 — Variant associated with a 2500 A M-Rect and suppressor application. This is a substantially different function and should not be substituted for 0-54341-21.
- Reliance Electric 0-54341-2 — Variant identified as a full-wave bridge board. Related by part-family numbering, but functionally different from the contactor coil driver.
- Allen-Bradley 23P-DC-CLDRV-3 — Current replacement reference for obsolete O-54341-21. It drives the 74 VDC, 76 Ω low-resistance coil of the 417690-4R contactor.
- Allen-Bradley 23P-DC-CLDRV-2 — Related DC coil driver for a 74 VDC 417690-4R high-resistance coil configuration. It is not the same application as 0-54341-21.
- Allen-Bradley 23P-DC-CLDRV-1 — DC coil driver for specified General Electric brake-coil applications. It demonstrates the same replacement-driver family but uses a different coil application.
- Allen-Bradley 23P-DC-CLDRV-5 — 100 VDC coil driver for RA 417696 and 78460-series contactors. Different coil voltage, so it is not a substitute for 0-54341-21.
The Engineer’s Guide: Field Pitfalls to Avoid
⚠️ Do Not Substitute Based on “74 VDC” Alone
There are multiple 74 VDC contactor-driver configurations. Rockwell distinguishes the high-resistance and low-resistance 417690-4R coil applications.
How to avoid it: Verify the actual contactor number and coil resistance. For 0-54341-21, the documented target is the 417690-4R low-resistance 76 Ω coil.
⚠️ Do Not Confuse 0-54341-21 With the Base 0-54341 Board
The broader 0-54341 family contains other hardware descriptions, including rectifier boards.
How to avoid it: Require the complete 0-54341-21 identifier, not simply “0-54341.”
⚠️ Check the Contactor Coil Before Replacing the Driver
A shorted or partially damaged coil can overload the replacement driver.
How to avoid it: With the equipment safely de-energized, measure coil resistance and inspect the contactor terminals. Compare the result with the expected approximately 76 Ω value before connecting a replacement driver.
Frequently Asked Questions (FAQ)
What is Reliance Electric 0-54341-21?
It is a DC coil driver / contactor driver associated with legacy Reliance Electric drive equipment. Rockwell identifies it as the obsolete predecessor of 23P-DC-CLDRV-3.
What contactor does 0-54341-21 drive?
The documented application is the 417690-4R contactor with the low-resistance coil, approximately 76 Ω. The coil-drive voltage is 74 VDC.
What replaces 0-54341-21?
The Rockwell documentation identifies 23P-DC-CLDRV-3 as the replacement for obsolete O-54341-21.
For a plant repair, I would still compare the actual contactor, coil resistance, wiring, and mounting arrangement before treating the replacement as a plug-in solution.
Can I use 23P-DC-CLDRV-2 instead?
No—not simply because both are associated with 74 VDC coils. 23P-DC-CLDRV-2 is documented for a 417690-4R high-resistance coil, while 23P-DC-CLDRV-3 replaces 0-54341-21 for the low-resistance 76 Ω coil.
What should I check when buying a refurbished 0-54341-21?
Request:
- Actual board photographs
- Complete 0-54341-21 marking
- PCB revision/date code
- Contact/terminal condition
- Evidence of driver-output testing
- Compatible contactor confirmation
- Inspection for heat damage
- ESD-safe packaging
- Warranty terms
A visual inspection alone is weak evidence for a coil-driver board.
Is 0-54341-21 still manufactured?
It is documented as obsolete, with Rockwell providing as its replacement.
For procurement, clearly specify whether you require the original 0-54341-21, an unused legacy unit, or an approved replacement assembly.
What is the biggest replacement risk?
Using the wrong coil-driver configuration. The most important check is not just the PCB number—it is the combination of contactor model, coil voltage, and coil resistance. For 0-54341-21, the documented combination is 417690-4R + 74 VDC + 76 Ω low-resistance coil.
