Open rack - Quick start guide

This document provides formal instructions for integrating imperix power modules into an open rack type A. Designed to assist first-time users, the guide details essential mechanical considerations, auxiliary power supply requirements, and fault signaling configurations necessary for a successful installation.

Alternatively, modules may be housed in a Closed rack. This configuration offers enhanced safety features and facilitates tool-free power stage wiring through the use of integrated banana connectors.

What is inside an open rack?

An open rack is a metallic frame that can hold up to eight imperix power modules. It consists of:

• Eight sets of plastic mounting rails to slide power modules in.
• An auxiliary power supply that delivers +12V/5V to the modules.

Each slot is fully independent, though all share a common auxiliary power supply. Consequently, users may populate any slot and combine different types of power modules as required. Compatible Imperix products are listed in the table below.

Auxiliary power supply

Gemini said

Each of the eight modules utilizes a dual-output power supply for its auxiliary circuitry. The +12V output is dedicated to the fan and gate drivers, while the +5V output powers all remaining components.

The open rack utilizes a Delta Electronics PMT-D1V100W1AA power supply. This unit features a manual 115/230 VAC selector switch that must be configured to match the local grid voltage prior to operation.

In early 2026, the power supply was upgraded to the Mean Well ADS-15512 to support the increased power demands of PEB-800-40 modules. Unlike the previous model, this unit features a universal input range compatible with 115/230 VAC and does not require a manual selector switch.

The specifications of both models are summarized in the following table:

Inserting power modules into an open rack

PEB modules

All PEB modules share the same connectivity, as presented in the PEB-800-40 quick start guide:

• The switching node (AC).
• The DC bus positive (DC+), negative (DC-), and mid-point (N) terminals.
• Two analog outputs for the on-board sensors I_AC and V_DC (RJ-45 sockets).
• Two optical inputs for the high (H) and low (L) PWM gating signals.
• An optical fault output.

The integrated sensors do not utilize the Ethernet protocol for data transmission; rather, RJ-45 cables are capable of conveying analog signals due to their shielding and twisted-pair construction. A dedicated ±15V external supply is required for each onboard sensor, delivered through the RJ-45 cable. B-Box controllers provide this voltage. However, third-party controllers may necessitate an independent power source.

Gating signals are sent through standard 650 nm Plastic Optical Fibers (POF) or Plastic Clad Silica (PCS) fibers. No special coding is required: light ‘ON’ applies a positive voltage on the gate; light ‘OFF’ applies a negative one. Similarly, the optical fault output is in the light ‘OFF’ state to indicate a fault condition. This signal is retrievable by B-Box controllers utilizing an Optical Expansion Board.

Due to restricted access following installation, the AC and N terminals must be wired prior to mounting the module in the rack. Connections should be secured using an M4 screw, an anti-loosening washer, and a suitable ring terminal (e.g., RND 465-00635).

The next step is to slide the module into the rails and connect the auxiliary power supply, as shown below. The connector is keyed to ensure correct orientation and prevent the reversal of the +12V and +5V supplies.

Following installation, interconnect the modules using flat ribbon cables (TE connectivity 2205065-2) in a daisy-chain configuration to enable fault sharing across the system.

Finally, the DC bus terminals can be wired using either ring terminals or bus bars (sold separately).

PEN modules

Installation of PEN modules follows the same procedure as PEB modules, with the exception of the onboard voltage sensor configuration. PEN modules use two sensors to monitor either the upper or lower DC half-bus, depending on the position of two jumpers. As these jumpers are difficult to access once installed, the desired measurement output must be configured before sliding the module into the open rack.

PEH modules

In contrast to PEB and PEN modules, PEH power terminals are side-mounted, and the system does not utilize flat cables for fault sharing. The installation is therefore simplified as follows:

1. Slide PEH modules into the rack.
2. Connect the auxiliary power supply (+12V/+5V).
3. Wire the power stage using M4 fork terminals (e.g., Phoenix Contact 3240042).

Fault signaling

Six red LEDs are present on the front side of the module, under the mezzanine, indicating the origin of the fault, when applicable. The corresponding flags regroup the possible causes:

* only for PEB modules

The integrated logic generates a global fault indicator, which is made available via an optical output (see below). Fault clearance is performed by actuating the dedicated clear button, which is located on the mezzanine of any module.

PEB and PEN modules can be interconnected in a daisy-chain configuration using flat cables to manage the system-wide fault state and control. This mechanism ensures the propagation of the global fault flag and the clear fault signal across all connected units.

• Global Fault Propagation: The detection of any local fault condition results in the assertion of the global fault flag, subsequently disabling all modules within the rack.
• Centralized Fault Clearance: Acknowledging a fault on any single module initiates a simultaneous reset of the fault state across all neighboring modules connected in the chain.

Going further with the open rack…

A fully functional converter requires a controller, such as the B-Box 4, in addition to power modules. The following articles provide all the necessary information to build a complete converter with an open rack.

• B-Box 4 – Quick start guide (PN254)
• PEB-800-40 – Quick start guide (PN210)
• How to build a buck converter (PN119)