SEW-Eurodrive 8269920 Brake Rectifier Module (Type BG1.2)

Overview

SEW-Eurodrive part number 8269920 is the SEW-Eurodrive BG1.2 brake rectifier from the SEW BG brake control family. It takes a single-phase AC supply and produces the DC voltage that releases the spring-applied brake on SEW brake motors. The BG is a half-wave rectifier with overvoltage protection. SEW uses it on small motors where the brake release reaction time has no special requirements.

The module is compact and is normally mounted in the motor terminal box, next to the brake coil connections. Where the installation calls for it, the module can also be mounted in the control cabinet. If a rectifier fails, the brake may not release or apply correctly, so plant maintenance teams usually keep this module as a spare.

Key Features

• BG family half-wave brake rectifier with overvoltage protection
• Wide AC input range of 90 to 500 V AC
• DC output current rating 1.2 A
• Compact module for terminal box mounting
• Designed for SEW spring-applied brakes on small motors

Technical Specifications

Applications

• Brake supply on small SEW brake motors and gearmotors
• Conveyors, packaging machines and light material handling drives
• Hoists and positioning drives with spring-applied holding brakes
• Maintenance spare for SEW drive fleets in oil & gas, water, power and manufacturing plants

SEW-Eurodrive BG1.2 Selection Notes

In the SEW rectifier tables the BG 1.2 (black housing) covers 90 to 500 V AC with a maximum holding current of 1.2 A DC. SEW marks it for use with DT56 and DR63 motors or with the IS plug connector; the BG 1.5 covers 150 to 500 V AC for the other small frames, and BG 2.4 and BG 3 cover low brake voltages. The correct size therefore depends on brake voltage and holding current, not only on the BG name.

The BG is a plain half-wave rectifier with varistor overvoltage protection. It gives a DC output of roughly 42 % of the AC input and releases the brake in normal time; there is no over-excitation stage, so SEW recommends it for drives with occasional braking and infrequent starts. Where frequent cycling or hoisting is involved, SEW points to the BGE instead.

SEW-Eurodrive BG1.2 Installation and Wiring Notes

The rectifier has five terminals. When it is fed from the motor terminals it can be wired for normal or rapid brake application. Rapid application needs the DC circuit to be opened as well, which SEW implements with an auxiliary contact of the motor starter connected to rectifier terminals 4 and 5, or with a current or voltage relay in its place.

SEW warns that a rectifier can be damaged by heat and should not sit in the terminal box of motors with class H insulation, ambient temperatures above 40 °C or restricted air flow; a rail-mounted BMS rectifier in the control cabinet is the alternative. The AC voltage applied must match the brake voltage on the motor nameplate.

How the SEW-Eurodrive BG1.2 Brake Rectifier Works

SEW brakes are DC-operated, spring-applied disc brakes, but most motors are fed from an AC network. The SEW-Eurodrive BG1.2 brake rectifier closes that gap. It converts the single-phase AC supply taken from the motor terminals or from a separate supply into the DC voltage the brake coil needs. While the coil is energised, the magnetic force holds the pressure plate away from the brake disc and the motor turns freely. When the supply to the rectifier is switched off, the coil field collapses and the springs apply the brake.

The time it takes the brake to apply depends on how the circuit is switched. With AC-side switching only, the coil current decays slowly through the rectifier and application is delayed. With DC-side (AC and DC) switching, the DC circuit is opened as well and the brake applies much faster. This is why the wiring diagram matters as much as the rectifier type when a replacement is installed.

Checking a Suspected Faulty Rectifier

• Confirm the AC voltage at the rectifier input matches the brake voltage on the motor nameplate.
• Check the brake coil resistance and insulation before replacing the rectifier, since a shorted coil can destroy a new module.
• Inspect the terminal box for heat damage, moisture and loose connections.
• Verify the wiring for normal or rapid application against the SEW wiring diagram for the motor.

Typical Applications in Oman & the GCC

Small SEW brake motors are used throughout the region on conveyors, packaging and bottling lines, water treatment equipment, warehouse handling systems and auxiliary drives in oil, gas and power plants. In hot installations, the ambient-temperature guidance above is important: where terminal box temperatures run high, a cabinet-mounted rectifier is the safer choice.

Why Seven Star LLC

Seven Star LLC supplies SEW-Eurodrive brake rectifiers and brake motor spares to industrial customers across Oman and the GCC. Before we quote, we check the rectifier type against your motor nameplate, brake coil voltage and wiring diagram, because the correct module depends on the supply voltage and brake of each machine.

Request a Quote for SEW-Eurodrive 8269920 Brake Rectifier Module (Type BG1.2)

Submit a formal inquiry through our RFQ page with part number 8269920, the quantity, your SEW motor type and serial number, the brake type and the supply voltage of the brake circuit. We will confirm the correct SEW-Eurodrive BG1.2 brake rectifier for your application and send a detailed quotation.

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