Old Version Psu1 Power Supply Board 6SE7031-7HG84-1JA1 6SE70317HG841JA1 6SE7O31-7HG84-1JA1 6SE7 031-7HG84-1JA1

Siemens 6SE7031-7HG84-1JA1 | SIMOVERT MASTERDRIVES PSU1 Power Supply Module — Designs E–H, Multi-Voltage

Part Number: 6SE7031-7HG84-1JA1

Manufacturer: Siemens AG (Germany)

Product Type: PSU1 — Power Supply Unit 1 (Internal Auxiliary Power Module)

Product Range: SIMOVERT MASTERDRIVES 6SE70

Overview

The 6SE7031-7HG84-1JA1 is the PSU1 (Power Supply Unit 1) internal auxiliary power supply module for Siemens SIMOVERT MASTERDRIVES chassis drives of Designs E through H. This module derives its input from the drive's main supply — either the 3AC mains voltage (380–460V or 660–690V) or directly from the DC bus (510–620V or 890–930V) — and generates the regulated internal supply rails that power the drive's control electronics, gate drive circuits, cooling fan, and auxiliary circuits.

One of the most distinctive features of the 6SE7031-7HG84-1JA1 is its multi-voltage input capability.

The single PSU1 module operates across both standard industrial voltage classes: the 380–460V 3AC / 510–620V DC range used in most European and North American installations, and the higher 660–690V 3AC / 890–930V DC range used in large industrial plants and marine applications.

This dual-range design allows the same spare part to serve a broad population of MASTERDRIVES installations, simplifying spares inventory across mixed-voltage drive fleets.

Design E through H designates the chassis size range. In the MASTERDRIVES 6SE70 series, design sizes reflect physical cabinet dimensions and power ratings — Design E through H covers a substantial portion of the large-chassis drive range from approximately 90A to over 800A output current, spanning medium to high industrial power applications. The PSU1 module is positioned to serve all of these chassis sizes through a unified hardware design.

Key Specifications

PSU1 Function — Internal Drive Power Supply

In the SIMOVERT MASTERDRIVES architecture, the electronics box contains all of the drive's control and monitoring circuitry.

These circuits require stable, regulated DC supply voltages — typically ±15V, +5V, and +24V for control electronics, and additional voltages for the gate drive circuits and auxiliary relays. 

None of these voltages come from the external AC supply directly; they are all derived internally by the PSU1 module from the drive's main power.

The 6SE7031-7HG84-1JA1 achieves this through a switching power supply design that accepts the wide input range and converts it to the required output rails with isolation between the high-voltage input and the low-voltage control outputs.

This isolation is fundamental to safety — the control electronics connected to the 6SE7031-7HG84-1JA1's output must remain at safe potential levels even while the input side operates at hundreds of volts DC bus potential.

The PSU1 also manages the sequencing of internal power-up.

The drive's control electronics cannot operate during pre-charge of the DC bus capacitors, and the PSU1 coordinates the readiness signalling that tells the control boards when stable supply is available.

A healthy PSU1 ensures that the drive's control circuits power up in the correct sequence and with stable voltages from the first moment of operation.

Multi-Voltage Architecture — E through H Range

The MASTERDRIVES Design E through H chassis range was engineered for scalability across a wide power and voltage spectrum.

The same electronics box structure — housing the CUVC control module, PSU1, and option boards — is used across this range, with the power section (IGBTs, heatsink, capacitors) scaled to the drive's rated current.

The 6SE7031-7HG84-1JA1's ability to operate from either 380–460V or 660–690V 3AC supply means a single PSU1 part number services drives destined for different global market voltage requirements.

In large industrial facilities running 690V distribution, the same PSU1 module feeds drives that in a 400V facility would draw from the lower voltage range. 

This is a practical inventory advantage for maintenance departments managing drive fleets across multiple voltage environments.

Fault Diagnosis — PSU1 Failure Indicators

PSU1 failure in a MASTERDRIVES Design E–H drive produces a recognisable set of symptoms. Complete control dead — no PMU display, no relay activity, no fan response — with confirmed mains supply at the drive input is the primary indicator.

The PSU1 is the earliest point in the control chain, and its failure blocks all subsequent electronics.

Intermittent control behaviour — the PMU display flickering, the control ready state dropping briefly during operation, or the drive failing to hold its ready state — is the secondary symptom pattern, typically indicating a PSU1 that is failing rather than already failed.

Electrolytic capacitor degradation within the PSU1's switching supply is the most common component-level cause of this pattern.

FAQ

Q1: The drive powers up, the DC bus charges normally, but the PMU displays nothing and the control ready relay does not close. The internal DC bus voltage has been confirmed present. Is the 6SE7031-7HG84-1JA1 the fault?

With DC bus confirmed and zero control response, the PSU1 is the primary suspect.

Verify the 24V auxiliary supply at the PSU1's output connector — if this is absent or severely below nominal with confirmed input voltage present, the PSU1 has failed and requires replacement. 

Also check the PSU1's internal fuse if the module design includes one, as a blown fuse produces identical symptoms.

Q2: The 6SE7031-7HG84-1JA1 is described as suitable for both 380–460V and 660–690V drives. How does it know which voltage range it's operating from?

The 6SE7031-7HG84-1JA1 uses a wide-input switching regulator topology that automatically adapts to the input voltage within its specified range without any manual switching or configuration.

The module senses the input level and the internal regulation loop adjusts accordingly.

No jumper setting, DIP switch, or manual tap selection is required when the PSU1 is installed in either a 380–460V or a 660–690V drive.

Q3: The 6SE7031-7HG84-1JA1 was discontinued. Is there a current-production Siemens module that replaces it?

With MASTERDRIVES 6SE70 discontinued across the product range, Siemens does not offer a current-production direct replacement for the PSU1 through new product channels. Sourcing is through the aftermarket — specialist drive service and exchange companies holding tested and warranted units.

For sites running multiple Design E–H drives, holding at least one spare 6SE7031-7HG84-1JA1 is strongly advisable given the criticality of this component and potentially extended sourcing lead times.

Q4: After installing a replacement 6SE7031-7HG84-1JA1, the drive powers up but shows an immediate fault indicating supply undervoltage. What should be checked first?

A supply undervoltage fault immediately after PSU1 replacement typically indicates that the PSU1's output connector is not fully seated at the electronics box backplane.

The connector carries the main supply rails from the PSU1 to the control boards — a poorly seated connection produces low voltage readings on the supply monitoring circuits. 

Power down, discharge the DC bus, and reseat the output connector firmly before powering up again.

Q5: The 6SE7033-7EH series drive also uses a PSU1. Is the 6SE7031-7HG84-1JA1 the correct PSU1 for that chassis, or is it specific to the 6SE7031 series?

The 6SE7031-7HG84-1JA1 PSU1 module serves MASTERDRIVES chassis designs E through H as a range — the "6SE7031" prefix in the part number identifies the spare part itself, not a restriction to 6SE7031 series drives.

This PSU1 module is used across the full Design E–H chassis range, which includes 6SE7031, 6SE7032, 6SE7033, and 6SE7034 drives of the correct chassis size. 

Confirm the PSU1 part number against the drive's service documentation or the label on the installed PSU1 before ordering a replacement.