The Allen-Bradley 1746-P7 is an SLC 500 rack mount power supply. The nominal input voltage for this module is around 12 to 24 Volts DC and its input voltage range is around 10 to 30 Volts DC. It has current capacities of 0.46 Amps, 0.625 Amps, and 0.87 Amps at 24 Volts DC, as well as 2 Amps, 2.64 Amps, and 3.6 Amps at 5 Volts DC. The maximum real input power of this power supply is around 75 Watts at 24 Volts DC and 50 Watts at 12 Volts DC. This power supply also comes with a maximum inrush current of 20A, which is required for the device to turn on. At an input of 12 Volts DC it has CPU hold-up times of 1.37 milliseconds at zero Volts DC for a full load, 895 milliseconds at zero Volts DC for no load, 10 milliseconds at 9 Volts DC for a full load, and it is continuous at 9 Volts DC for no load. At 24 Volts DC input, the CPU hold-up times are 40 milliseconds at zero Volts DC for a full load, 1860 milliseconds at 0 Volts DC for no load, 790 milliseconds at 11 Volts DC for a full load, and continuous at 11 Volts DC for no load.

Soldered into place is the power supply’s fuse protection which protects the module against short-circuit-related fire hazards. The entire 1746-P7 power supply measures 85 x 140 x 140 millimeters and it weighs 1.1 kilograms or 2.5 pounds. Up to two 14 AWG wires can be connected per terminal to this power supply. It also has an operating temperature range of 0 to 60 degrees Celsius and a storage temperature of -40 to 85 degrees Celsius. Note that the power supply’s current capacity is derated by 5% when the temperature is greater than 55 degrees Celsius. A non-condensing relative humidity of 5 to 95% is present with the 1746-P7 power supply. Using an isolation transformer is highly recommended to isolate and protect the power supply from voltage surges. These power surges may damage the power supply when switching inductive loads like solenoids, motor starters, motors, and relays. In case of undervoltage for the 1746-P7 power supply when the input voltage it receives falls somewhere between 4 and 9 Volts DC for a time longer than the CPU hold-up time, the SLC controller connected to it will turn off and will only turn on when the input voltage reaches 11 Volts DC.

The 1746-P7 is an SLC 500 Power supply which is the most sophisticated power supply in the SLC 500 power supply catalog.

This power supply is powered by a DC supply voltage ranging from 10 - 30VDC. The typical line power requirement of this power supply module differs according to the voltage input. For 12VDC input, the input line requirement is 50 VA while 75 VA for 24VDC input. The internal current capacity also differs according to the input level. If used with a 12VDC input, the internal current capacity is 12V dc input: 2.0 A at 5V dc 0.46 A at 24V dc while at 24V dc input: 3.6 A at 5V dc 0.87 A at 24V dc.

When wiring input power to the power supply, use 1.68 mm or #14 AWG Copper wire. Tighten terminal screws to 0.8 Nm (7 lb-in). Perform power wiring only when incoming power supply is turned OFF.

Since the 1746-P7 is supplied with a DC voltage, the hold time activates when the input voltage drops within the range of 4VDC to 9VDC. When this happens, the controller turns OFF and will not resume or turn ON until voltage has reached 11VDC.

Standard installation of any SLC Power supply is in the leftmost of the rack. It does not occupy a slot though it connects to the backplane slot. Slot counting starts with Slot Zero (0) which is reserved for the Programmable Logic Controller’s (PLC) processor or communication adapter such as Remote I/O (RIO), Data Highway Plus (DH+) and Ethernet.