Purchase now: Allen Bradley 1746-P4 High-Capacity Power Supply
Purchase now: Atlantechdrives provides you the 1746-P4, the most powerful AC-to-DC system power supply manufactured by Allen Bradley for the SLC 500 automation family. When dealing with heavily loaded 10-slot or 13-slot chassis completely populated with high-density output modules, specialty communication modules (like Ethernet or ControlNet), and power-hungry analog cards, standard power supplies will fail to meet the backplane demand. The 1746-P4 steps in to deliver a massive 10.0 Amps at 5V DC and 2.88 Amps at 24V DC. This heavy-duty unit guarantees that complex, large-scale industrial panels have the ultra-stable, highly regulated voltage they need to run continuous PID loops and motion control logic without experiencing brownouts or CPU hardware faults.
Technical Specifications of the 1746-P4
The 1746-P4 represents the pinnacle of the SLC 500 power supply lineup. It takes standard factory AC power and isolates it completely from the PLC electronics. Due to its high capacity, it features advanced thermal management and a significantly larger internal transformer compared to the P1 or P2.
- Part Number: 1746-P4
- Component Type: High-Capacity System Power Supply
- Compatible System: Allen Bradley SLC 500 (1746 Chassis)
- Input Voltage (Selectable): 85…132V AC or 170…265V AC
- Input Frequency: 47…63 Hz
- Backplane Output Capacity (5V DC): 10.0 Amps (Maximum capacity)
- Backplane Output Capacity (24V DC): 2.88 Amps
- User 24V DC Power: Isolated external supply (200 mA limit)
- Hold-up Time: 20 milliseconds at full load
Expert Installation Advice: Chassis Airflow and Thermal Derating
Pushing 10 Amps of DC power generates significant heat. Expert Tip: The 1746-P4 is a large, heavy power supply that relies heavily on passive convection cooling (the «chimney effect»). When installing the P4, you must ensure absolute adherence to Allen Bradley’s panel spacing guidelines. There must be a minimum of 6 inches (15.3 cm) of free clearance above and below the chassis to allow hot air to escape. If you mount wiring ducts too close to the top of the P4, the heat will become trapped, degrading the internal electrolytic capacitors and drastically reducing the lifespan of the power supply. Always use slot fillers (1746-N2) in empty rack slots to maintain the engineered airflow tunnel.
Maintenance and AC Line Quality
Like the P1 and P2 models, the 1746-P4 utilizes a physical jumper selector to switch between 120V AC and 240V AC input power. This must be checked and set manually prior to installation. If a machine with a 1746-P4 starts randomly faulting or rebooting during high-production periods, it is highly recommended to check the input AC line quality. While the P4 has a 20ms hold-up time, severe plant-wide voltage dips caused by large motors starting will cause the P4 to gracefully shut down the backplane to protect the processor.
Frequently Asked Questions (FAQs)
Q: Does the 1746-P4 require a different chassis than the P1 or P2?
A: No, it mounts on the exact same two mounting tabs on the left-hand side of any standard 1746-A4, -A7, -A10, or -A13 expansion chassis.
Q: Can I parallel two 1746-P4 power supplies for 20 Amps of power?
A: No. The SLC 500 backplane architecture does not support redundant or parallel power supplies on a single chassis. If you exceed 10 Amps, you must split your I/O into a secondary chassis using an interconnect cable (1746-C7 or -C9) and power that second chassis with its own dedicated power supply.
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This high-output AC supply is technically engineered for large 13-slot racks or the 1746-A10 10-slot chassis.
