1746-P3 — SLC 500 DC Input Power Supply, 24V DC

The 1746-P3 is a DC-input power supply for the SLC 500 modular chassis system, accepting 19.2–28.8V DC and converting it internally to the regulated 5V and 24V backplane rails that power every installed module. It mounts to the left of the chassis without occupying any of the numbered I/O slots, the same physical position used by every SLC 500 power supply variant regardless of input type.

Specifications

Parameter	Value
Part Number	1746-P3
Input Voltage	19.2–28.8V DC
Backplane Output	3.6 A @ 5V DC, 0.87 A @ 24V DC
Line Power Requirement	90 VA
Max Inrush Current	20 A
Isolation	600V AC RMS for 1 second
CPU Hold-up Time	5 ms (full load), 1000 ms (no load)
Fuse Protection	Internal, pre-installed (1746-F3 replacement compatible)
Operating Temperature	0°C to 60°C (5% derate above 55°C)

Why a 24V Input Power Supply Has a Place in an SLC 500 System

Most SLC 500 panels run from standard AC mains, but a meaningful number of installations — mobile equipment, remote skids running off battery or DC distribution, or panels integrated into a larger system already standardized on 24V DC bus power — need a supply that accepts DC input directly rather than converting from AC first. The 1746-P3 fills that role, taking a 24V DC nominal input and producing the same regulated backplane rails that any other SLC 500 power supply variant provides, so the rest of the chassis and its modules operate identically regardless of which power supply type is installed.

The CPU hold-up time specification matters in installations where the DC input source itself might experience brief interruptions — 5 ms at full load is enough to ride through very short transients without the controller dropping out, though anything longer than that window will cause the SLC processor to halt until input voltage is restored, after which it resumes automatically.

FAQ

Q: Does this power supply provide a 24V DC user power output for field devices?

No. The 1746-P3 does not include a separate 24V DC user power output for external devices — its output is dedicated entirely to backplane power for the installed SLC 500 modules.

Q: What happens if the input voltage drops below the rated range?

If input voltage drops below range for longer than the CPU hold-up time, the controller stops scanning and disables outputs. Normal operation resumes automatically once input voltage returns to the rated range.

Q: Does this power supply occupy one of the chassis's numbered slots?

No. It mounts to the left side of the chassis in a dedicated position, separate from and not counted among the chassis's numbered I/O slots.

Q: What fuse is used inside this power supply, and can it be replaced?

A fuse is pre-installed internally and can be replaced with the equivalent rated component if it fails — verify the exact replacement fuse rating against the unit's documentation before substituting.

1746-P3 Genuine New SLC 500 Power Supply Module Ser.A 1746P3