1756-PA75 — 1756 AC Input Power Supply, 75W

The 1756-PA75 is a 75W AC-input power supply for the 1756 Logix chassis system, converting line voltage to the regulated 5V and 24V DC rails that the backplane distributes to every installed module. It's the standard choice for 1756 builds where AC power is the available panel input and the planned module mix fits within its 75W backplane budget — a common configuration for mid-sized chassis with a processor, communication module, and a moderate I/O complement.

Specifications

Parameter	Value
Part Number	1756-PA75
Input Voltage	AC (85–265V AC, wide range)
Output Power	75 W total backplane budget
Output Rails	5V DC and 24V DC backplane
Mounting	Dedicated chassis power supply slot (1756 chassis)
Operating Temperature	0°C to 60°C

Installation Notes

Installs in the chassis's dedicated power supply slot — physically and electrically separate from the numbered module slots.
Verify AC input wiring matches the panel's available voltage within the supply's wide input range before connecting.
Leave margin in the power budget calculation for future module additions rather than sizing exactly to the current module list — a fully consumed power budget at commissioning leaves no room for later expansion without a supply swap.
Check for a status LED or diagnostic indicator on the supply itself as a first troubleshooting step if the chassis fails to power up — many backplane communication issues trace back to a power supply fault rather than a module problem.

FAQ

Q: Can the 1756-PA75 be used with a redundant chassis configuration?

For redundant 1756 systems, a redundant-rated power supply variant (carrying an "R" suffix in its catalog number) is required instead of the standard PA75 — verify the specific redundancy architecture's power supply requirements before specifying.

Q: What happens if the total module backplane draw exceeds 75W?

Exceeding the rated capacity risks unreliable module operation, intermittent backplane communication faults, or the supply tripping its internal protection. Recalculate the module list against the supply's rating and either reduce the module count or move to a higher-capacity supply before commissioning.

Q: Does this supply also provide power to field I/O devices?

No. The 1756-PA75 powers the backplane logic circuitry of installed modules only. Field-side power for sensors, actuators, and other I/O devices comes from separate, externally-supplied 24V DC sources connected at each module's terminal base.

Q: Is a DC-input version available for panels without AC power at the chassis location?

Yes, DC-input variants exist in the 1756 power supply family for installations where a DC bus is the available panel supply rather than AC — select the model matching the actual input available at the installation.

1756-PA75 1PCS New 1756PA75 AC Power Supply Module Fast delivery