Overview
Manuals
Redundant PSMs
CMOS Backup
CE Use Limits
Features:
- Exact catalog identity 51401140-250: 115 Vac, 16 A AC-only power system with primary and redundant PSMs.
- Conformally coated execution with separate DC-output status indication and card-file power distribution.
- Alkaline CMOS memory retention, no optional 48 Vdc operating-power battery backup, and an explicit restriction against CE-compliant applications.
The Honeywell MC-PAR121 is a legacy cabinet power-system assembly, not a generic 24 V input card. Honeywell's exact-model table associates it with part number 51401140-250 and identifies the 115 Vac, 16 A redundant configuration. The AC-only system drawing shows separate primary and redundant power-supply modules, DC-output status LEDs and power distribution to the card-file backplanes. Its conformally coated execution is identified in the manufacturer's assembly table; coating does not remove the separate electrical and regulatory restrictions that apply to this design.
For maintenance, distinguish an available replacement component from the complete configured power-system scope. Verify both supply positions, the distribution assembly, connection condition and cabinet loading before the qualified installation procedure is planned. The alkaline backup described for this architecture preserves CMOS memory; it is not an uninterruptible source for the operating cabinet load. Honeywell also states that the AC-only system does not offer the optional 48 Vdc battery-backup module and must not be used in CE-compliant applications. These restrictions should remain part of the purchasing and engineering review even when a visually similar spare is available.
The MC-PAR121 Honeywell AC-Only Redundant Power System may still be available for purchase and support from Moore Automated Company beyond End-Of-Life (EOL) by the manufacturer (OEM).
Honeywell MC-PAR121 official technical documentation and product links.
This multi-page Honeywell technical document contains the exact model and its technical data. Apply the values to the supplied type number and verify its revision before installation.
The exact model is the 16 A AC-only arrangement with primary and redundant PSMs. Redundancy describes the supply arrangement; it does not establish a doubled 32 A cabinet rating or guarantee survival of every shared-source or distribution fault. Check the installed loading and the complete power path, including the distribution assembly and connections, when assessing a spare or a maintenance procedure.
Alkaline batteries provide CMOS memory retention in the AC-only architecture. They must not be advertised as the optional 48 Vdc operating-power backup used by other Honeywell power systems. The cited manual also distinguishes this design from rechargeable NiCad CMOS backup. Confirm the installed battery arrangement and its maintenance requirements separately from the cabinet's AC supply and any external UPS.
Honeywell explicitly excludes the AC-only power system from CE-compliant applications. In the conformally coated model table, MC-PAR121 appears under non-CE part number 51401140-250, with no CE-compliant part number in that row. Do not infer CE approval from the broader manual title, from conformal coating, or from a different power-system model shown on the same page.
