Honeywell 05701-A-0405 16-Way 50 W Power Supply

Description

Key Technical Specifications

Honeywell documentation identifies 05701-A-0405 as the 16-way AC-to-DC Power Supply Unit for System 57. The basic unit contains one 50 W switched-mode AC-to-DC module and accepts either 85–264 V AC at 47–440 Hz or 110–340 V DC input.

The PSU provides nominal 24 V DC output and includes overload and overvoltage protection. Honeywell specifies an upgrade path using additional 50 W modules; the 16-way assembly can ultimately reach 200 W when the additional subunit and modules are fitted.

Product Introduction

The Honeywell 05701-A-0405 is a 16-way, 1U, 19-inch AC-to-DC Power Supply Unit designed for the Honeywell System 57 / 5701 gas detection platform. It converts a wide-range AC or DC input into regulated 24 V DC power for System 57 racks and connected control equipment.

The base configuration provides 50 W and can be expanded in 50 W increments. A second 50 W module raises capacity to 100 W, while the 05701-A-0441 subunit allows the 16-way assembly to reach 200 W. The model is now a legacy/discontinued component, so replacement condition and exact configuration should be verified before ordering.

Installation & Configuration Guide

Stage 1: Pre-Installation Preparation — Allow 10 Minutes

⚠️ Safety First: The 05701-A-0405 handles potentially hazardous AC mains voltage. Notify operations, place the System 57 installation in the approved maintenance state, isolate the incoming supply, apply LOTO, and verify absence of voltage before opening or removing the PSU.

Honeywell specifies that the 05701-A-0405 accepts 85–264 V AC or 110–340 V DC. Do not assume the unit is safe because the System 57 control cards operate at 24 V DC.

Tools Required:

• ESD wrist strap
• PH1/appropriate cabinet screwdriver
• Calibrated multimeter
• Insulated electrical tools appropriate to the installation
• Wire labels
• Smartphone for wiring photographs
• Appropriate torque screwdriver where specified by the terminal hardware

Data Backup:

1. Record the PSU part number: 05701-A-0405.
2. Photograph the complete rear wiring arrangement.
3. Record the incoming AC/DC supply type and measured voltage.
4. Record the 24 V DC output connections.
5. Record the number and type of installed 50 W modules.
6. Determine whether the PSU is configured for 50 W, 100 W, or a higher expanded capacity.
7. Photograph all earth connections before removal.

⚠️ Do not replace the PSU based solely on the part number. Check the actual module population and power requirement. A replacement with only the base 50 W configuration may not reproduce a previously upgraded installation.

Stage 2: Removing the Old Power Supply — Allow 10 Minutes

1. Open the upstream disconnect and apply LOTO.
2. Verify the AC/DC input is de-energized with a calibrated multimeter.
3. Verify the nominal 24 V DC output has fallen to a safe level.
4. Photograph the AC input terminals and 24 V DC output terminals.
5. Label each conductor before disconnecting it.
6. Disconnect the three-core AC input cable.
7. Disconnect the two-core DC output cable.
8. Disconnect the protective earth connection.
9. Remove the rack mounting hardware.
10. Carefully withdraw the 05701-A-0405 from the 19-inch rack.

Honeywell specifies a three-core rear input connection and a two-core rear 24 V DC output connection for these power supply units.

⚠️ Do not work from memory on the mains wiring. Photograph the actual installation before disconnecting anything.

Stage 3: Installing the New Power Supply — Allow 10 Minutes

1. Verify that the replacement is marked 05701-A-0405.
2. Compare the replacement PSU’s physical configuration with the removed unit.
3. Confirm the number of installed 50 W modules.
4. Check that the required mounting position is the 16-way, 19-inch System 57 configuration.
5. Install the PSU into the rack.
6. Secure the mounting hardware.
7. Reconnect the protective earth.
8. Reconnect the AC input conductors according to the original wiring documentation.
9. Reconnect the 24 V DC output conductors.
10. Verify polarity and terminal tightness before energization.

Self-Checklist:

• 05701-A-0405 verified
• 16-way configuration verified
• 50 W / 100 W / 200 W capacity verified
• Input voltage verified
• Protective earth connected
• AC wiring verified
• 24 V DC polarity verified
• Terminals secured
• Rack mounting secured
• Downstream load within PSU capacity

Stage 4: Power-On & Testing — Allow 10 Minutes

1. Measure the incoming supply before connecting the PSU.
2. Confirm the input falls within the specified range.
3. Restore power according to the approved site procedure.
4. Measure the PSU’s DC output.
5. Confirm approximately 24 V DC within the specified ±10% range.
6. Check for abnormal heating, noise, odor, or repeated overload behavior.
7. Energize the System 57 rack.
8. Confirm installed control cards start normally.
9. Check for card Fault or Inhibit indications.
10. Confirm the System 57 channels operate normally under their approved functional test.

The PSU incorporates overload protection that operates above 105% of its rating with automatic recovery, and overvoltage protection above 115%. Repeated cycling into protection should be treated as a load or PSU problem, not as normal operation.

Technical Replacement Traps

1. ⚠️ Confusing 05701-A-0405 With 05701-A-0406

The 05701-A-0405 is the 16-way, 19-inch version. The 05701-A-0406 is the 8-way, half-19-inch version. They serve the same System 57 PSU family but are mechanically different.

2. ⚠️ Forgetting the Existing Power Upgrade

A base 05701-A-0405 contains a 50 W module. If the original installation uses additional modules or a subunit, replacing it with a basic 50 W configuration can leave the rack underpowered. Honeywell provides a documented path to 100 W and 200 W.

3. ⚠️ Measuring Only the No-Load Output

A PSU can show approximately 24 V DC with no load and still fail when the System 57 rack is energized. Check the output during actual system operation.

4. ⚠️ Ignoring Inrush Current

The published specification gives approximately 30 A at 230 V AC at 50 W full load. Verify upstream protection and distribution equipment rather than assuming the steady-state 50 W rating tells the whole story.

5. ⚠️ Treating 24 V DC as the Only Relevant Specification

The output is 24 V DC, but the installation must also satisfy the input-voltage range, grounding arrangement, available power, rack capacity, and environmental requirements. The 05701-A-0405 is an AC/DC rack-mounted power assembly, not simply a generic 24 V DIN-rail supply.

05701-A-0405

05701-A-0405

Frequently Asked Questions (FAQ)

1. What is the Honeywell 05701-A-0405 used for?

The 05701-A-0405 is the 16-way AC-to-DC Power Supply Unit for Honeywell System 57. It supplies regulated 24 V DC power to the System 57 rack and its installed control/interface cards.

2. What input voltage does the 05701-A-0405 accept?

It accepts 85–264 V AC at 47–440 Hz or 110–340 V DC. No manual input-voltage adjustment is required within those specified ranges.

3. Is the 05701-A-0405 a 50 W or 200 W power supply?

The base configuration is 50 W. The 16-way PSU can be expanded to 100 W by adding another 50 W module. With the appropriate 05701-A-0441 subunit and additional 50 W module, the assembly can reach 200 W.

4. Is 05701-A-0406 a direct replacement for 05701-A-0405?

No, not as a mechanical replacement. 05701-A-0406 is the 8-way, half-19-inch PSU, while 05701-A-0405 is the 16-way, full 19-inch unit. Confirm rack dimensions and the installed System 57 architecture before selecting an alternative.

5. Is Honeywell 05701-A-0405 obsolete?

Yes. Current distributor catalogs identify the 05701-A-0405 as discontinued, although new-surplus stock may still exist in the secondary market.

6. Can I install a generic 24 V DC power supply instead?

Technically, the System 57 load only requires an appropriate DC supply, but a generic replacement is not automatically a drop-in substitute. The original 05701-A-0405 provides the correct rack-mounted mechanical arrangement, wide-range input, protection functions, grounding provisions, and System 57 integration. Any engineered substitute should be checked against the complete electrical and mechanical requirements.

7. How do I distinguish New Original from Refurbished stock?

Ask for photographs of the actual 05701-A-0405, including its identification label, power-module configuration, and physical condition. New Original/New Surplus should mean unused OEM stock; Refurbished means previously used equipment that has been inspected or tested. For a discontinued PSU, obtaining actual-unit photographs and test results is more useful than relying on a generic catalog photograph.