Purchase now: Allen Bradley 1746-P1 SLC 500 Power Supply
Purchase now: Atlantechdrives provides you the 1746-P1, the foundational power supply unit designed by Allen Bradley to drive the legendary SLC 500 programmable logic controller ecosystem. This rugged, chassis-mounted power supply is responsible for converting incoming AC line voltage from the factory floor into the highly regulated 5V DC and 24V DC power required by the PLC processor, memory modules, and I/O cards via the backplane. Compatible with all 1746 chassis sizes (4, 7, 10, and 13 slots), the 1746-P1 is the beating heart of thousands of industrial control panels globally, providing stable, filtered power to ensure your automation logic executes flawlessly without brownouts or voltage dips.
Technical Specifications of the 1746-P1
The 1746-P1 is engineered to accept a wide range of standard AC input voltages, making it suitable for global deployment. It mounts securely on the left side of the SLC chassis and features built-in overcurrent and overvoltage protection to shield your expensive PLC cards from incoming electrical surges.
- Part Number: 1746-P1
- Component Type: System Power Supply
- Compatible System: Allen Bradley SLC 500 (1746 Chassis)
- Input Voltage Range (AC): 85…132V AC or 170…265V AC (Selectable)
- Input Frequency: 47…63 Hz
- Output Capacity at 5V DC: 2.0 Amps
- Output Capacity at 24V DC: 0.46 Amps
- Inrush Current (Max): 20 Amps
- User Power Output: Includes 24V DC external terminals for field sensors
Expert Installation Advice: The Fatal Jumper Switch
A simple oversight during installation can instantly destroy this unit. Expert Tip: The 1746-P1 does not auto-sense the incoming AC voltage. It features a physical, red selector jumper located on the circuit board (visible before mounting it to the chassis) that toggles between 120V AC and 240V AC input modes. Out of the box, it is often set to 120V AC. If you are installing this power supply in a European facility or on a machine utilizing 240V AC control power, and you fail to move that jumper to the 240V position, applying power will instantly blow the internal primary transformer and permanently destroy the power supply. Always visually verify the jumper position before sliding the unit into the chassis and turning on the main breaker.
Maintenance and Power Budgeting
When upgrading a machine by adding new I/O cards to the SLC chassis, you must perform a power budget calculation. The 1746-P1 is a reliable but lower-capacity supply, providing only 2.0 Amps at 5V DC. If you fill a 10-slot rack with high-density analog modules or 32-point DC modules, their combined backplane current draw will easily exceed 2.0 Amps. When the supply is overloaded, the PLC CPU will fault and the system will shut down. If your calculation exceeds the P1’s capacity, you must upgrade to a larger supply, such as the 1746-P2 or 1746-P4.
Frequently Asked Questions (FAQs)
Q: What are the «User Power» terminals on the front for?
A: The 1746-P1 provides a small amount of isolated 24V DC power (up to 200 mA) at the front terminal block. This is highly useful for powering a small number of external input sensors (like photoelectric eyes or limit switches) without needing to install a separate 24V DIN-rail power supply in the cabinet.
Q: Does the 1746-P1 have a replaceable fuse?
A: Yes, it features an internal, replaceable slow-blow fuse to protect the primary circuit. However, if the fuse blows repeatedly, there is likely a hard short on the backplane or within one of the I/O modules.
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This standard AC power supply provides the necessary backplane current for processors like the SLC 5/01 CPU.
