SEW-Eurodrive BSG Brake Rectifier 24VDC 5A (8254591)

Overview

SEW-Eurodrive part number 8254591 is the SEW-Eurodrive BSG brake rectifier, a BSG brake control unit. It switches the DC supply to the brake coil of SEW brake motors directly from a 24 V DC source. Unlike the BG and BGE rectifiers, the BSG does not rectify AC mains. It is used where a 24 V DC control supply is already available at the motor or in the control cabinet.

According to SEW-Eurodrive, the BSG gives the same brake release reaction times as the BGE brake rectifier. It is standard on motor frame sizes 112M and larger and optional on frame sizes 71 to 100. The unit is part of the SEW brake control programme and works with the spring-applied BM(G) brakes on SEW motors and gearmotors.

Key Features

• BSG brake control unit for 24 V DC supply (20–30 V DC)
• Rated current 5 A
• Brake release reaction times equivalent to the BGE rectifier
• Standard on SEW motor frame sizes 112M and larger, optional on sizes 71 to 100
• No separate AC-to-DC conversion needed where 24 V DC is available

Technical Specifications

Applications

• Brake control on SEW brake motors and gearmotors in installations with a 24 V DC control supply
• Conveyors, hoists, cranes and automated handling equipment
• Replacement spare when a brake releases slowly or does not release
• Drive systems in oil & gas, water treatment, power and process plants across the GCC

SEW-Eurodrive BSG Selection Notes

The SEW technical note on brake rectifiers places the BSG in the group of control units for 24 V DC brake voltage, where no rectification takes place. It protects the coil against overvoltage and adds a fast-release function: the brake is released with a short over-excitation and then held at reduced current. Maximum holding current is 5.0 A and the housing colour is white.

The same document assigns units to brake sizes. For 24 V DC brakes of size BMG05 to BMG4 (motor frames up to 100), the standard unit is the simpler BS24, which gives only overvoltage protection and normal release time. For BMG8 up to BM62 (motor frames 112 and larger) the BSG is the standard, and it is optional on frames 71 to 100.

Current demand should be checked against the 24 V supply. The SEW operating instructions give the DC brake current in BSG operation as 2.77 A for BMG8, 4.15 A for BM15 and 4.00 A for BM30 to BM62.

SEW-Eurodrive BSG Installation and Wiring Notes

The BSG may be installed either in the motor terminal box or in a control panel. SEW advises against fitting brake control electronics in the terminal box of motors with class H insulation, motors running in ambient temperatures above 40 °C, or motors with restricted air flow; in those cases a cabinet-mounted unit should be used. The brake coil has three leads (red, white and blue) because it consists of an accelerator coil and a holding coil; all three are connected to the control unit according to the wiring diagram supplied with the motor.

Why Seven Star LLC

Seven Star LLC supplies SEW-Eurodrive brake control units, including the BSG type, for maintenance programmes across Oman and the GCC. Before we quote, we check the rectifier type, control voltage and brake coil data against your motor nameplate and wiring diagram, because the DC-input BSG cannot be used in place of the AC-input BG, BGE or BSR units.

Request a Quote for SEW-Eurodrive BSG Brake Rectifier 24VDC 5A (8254591)

Send a formal inquiry through our RFQ page with part number 8254591, the quantity, your SEW motor type and serial number, the brake type and your control voltage. Our engineers will verify the correct SEW-Eurodrive BSG brake rectifier for your circuit and provide a quotation.

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How the SEW-Eurodrive BSG Brake Rectifier Controls the Brake

SEW brake motors use a spring-applied, electromagnetically released disc brake. When the coil is de-energised the springs press the brake disc and the motor shaft is held; when the coil is energised the armature plate is pulled in against the springs and the shaft is free to turn. The SEW-Eurodrive BSG brake rectifier is the electronic switching device placed between the 24 V DC supply and the brake coil. On release it first applies a high current to the accelerator section of the coil, which gives a short release time, and then switches to the holding section so that the coil does not overheat during long running periods. This is why SEW states that the BSG achieves release times comparable to the BGE rectifier used on AC supplies.

Selection and Ordering Checklist

• Confirm the available control voltage is 24 V DC within the permitted tolerance band at the motor terminal box, allowing for voltage drop on long cables.
• Check the brake type and coil voltage on the motor nameplate; the BSG is intended for 24 V DC brake coils.
• Note the motor frame size and where the existing brake controller is fitted (motor terminal box or control cabinet).
• For hoists and vertical axes, review the brake application time and whether DC-side switching is required by the original wiring diagram.

Seven Star LLC supplies SEW-Eurodrive brake control units across Oman and the GCC; send the motor nameplate and existing part number and our team can help confirm the correct ordering code.