Finder 78.Y3.1.440.2414 24 V 480 W Three-Phase Power Supply

480 W from a three-phase 400 V feed, with a DC OK contact

The Finder 78.Y3.1.440.2414 is an industrial three-phase switch mode power supply that provides 24 V DC at 20 A, a rated 480 W. Its input accepts 380 to 480 V AC nominal over an operating range of 340 to 550 V AC, and dual-phase operation is also listed. A double-stage design with active power factor correction gives a power factor of 0.88 or higher and an efficiency of 92% at 400 V AC.

Finder fits the unit with an auxiliary DC OK feedback contact, constant-current output limiting, a 30% boost current for 3 seconds and a varistor for overvoltage. It sits between the 78.X3 (240 W) and the 78.Z3 (960 W) in the same datasheet block, and all three share the 35 mm rail mounting.

Technical specifications

When a three-phase 24 V supply is the better choice

A 480 W single-phase supply loads one line of a distribution board, while a three-phase unit spreads the same power over all conductors and draws only about 0.85 A per phase at 400 V AC. The wide 340 to 550 V AC range tolerates sagging or high feeders, and the DC OK contact lets a PLC or monitoring relay confirm the 24 V rail before a machine starts. The datasheet also allows two supplies to be paralleled through external diodes for more current or redundancy.

Wiring and protection points

Check the connection scheme before commissioning: the datasheet marks the unit for three-phase use and mentions dual-phase operation as a possibility, so confirm the permitted configuration and any derating in the technical documentation. Inrush is 50 A peak at 400 V AC, which influences the upstream breaker characteristic. Stand-by consumption is 9 W, which is worth counting when many units remain energised overnight. The output can be trimmed from 24 to 28 V; set it after measuring the voltage drop to remote loads rather than raising it blindly.

How the Finder 78.Y3.1.440.2414 works

The 78.Y3.1.440.2414 is a switch mode power supply. It takes three-phase AC, rectifies it, and a double-stage circuit with active power factor correction cuts the reactive load on the feed. A high-frequency stage then converts the energy to a steady 24 V DC output at up to 20 A. An output current limit protects the unit in an overload, a 30 percent boost current lasts 3 seconds to start loads with a high inrush, and a DC OK contact reports the output status to a controller.

Where the Finder 78.Y3.1.440.2414 is used

• Control cabinets with PLCs and I/O modules
• Machine builders and panel builders
• Process plants with 400 V three-phase feeders
• Sensors, relays and valve coils at 24 V DC
• Installations with weak or varying mains

Selection checklist for the 78.Y3.1.440.2414

• Output of 24 V DC at 20 A, which is 480 W
• Adjustable output from 24 to 28 V DC
• Input of 380 to 480 V AC, three phase
• Operating range of 340 to 550 V AC
• Efficiency of 92 percent at 400 V AC
• Ambient temperature from -30 to 70 degrees C, with derating
• Width of 85.5 mm for 35 mm rail mounting
• DC OK feedback contact

Installation, commissioning and maintenance notes

Snap the unit onto the 35 mm rail with free space above and below for air flow. Connect the three phases and the earth to the input terminals, and the 24 V output to the load, using box clamp terminals. Check the output voltage with no load and at full load, and adjust it if the loads need more than 24 V. Wire the DC OK contact to the controller input, and check the derating curve when the cabinet runs hot.

Requesting a quotation for the Finder 78.Y3.1.440.2414

Please send the output current, the supply voltage and the quantity needed. Seven Star LLC serves industrial customers in Oman and the GCC and replies with a quotation based on the information provided.

78.Y3.1.440.2414 output quality

The voltage ripple is 150 mV at full load, and the output varies by less than 1 percent between no load and full load.

78.Y3.1.440.2414 hold-up time

The unit holds the output for 20 ms at full load after a mains dip, which bridges short interruptions.

78.Y3.1.440.2414 input current

At 400 V AC the input current is at most 0.85 A, and the inrush peak is 50 A.

78.Y3.1.440.2414 insulation

The dielectric strength is 3000 V AC from input to output and 2000 V AC from input to earth.

Power supply records for 78.Y3.1.440.2414

Keep the ordering code, the output setting and the date of installation with the panel file.

Choosing the right 78.Y3.1.440.2414 rating

Add up the load current, leave a margin for future loads, and compare the total with 20 A at the cabinet temperature.

Documents and quotation

The attached Finder datasheet covers the whole 78 series with outline drawings, derating diagrams and ordering information. For a quotation on 78.Y3.1.440.2414, send the quantity, the three-phase voltage and frequency at the site, the 24 V load current with peaks and the cabinet temperature. Related supplies are listed under Power Modules.