LENZE BG10 Bridge rectifier

The part number Lenze BG10 refers to a Bridge Rectifier (Gleichrichter) used primarily for controlling electromagnetic brakes on Lenze AC motors and gearmotors.

It converts the AC supply voltage into the DC voltage required to release the motor brake.

Quick Technical Specifications

Function: Full-wave bridge rectification.

Mounting: Designed for mounting inside the motor terminal box or on a DIN rail (depending on the housing version).1

Connection: Typically features a 6-pole terminal configuration.2

Max Input Voltage: Usually rated up to 270V AC.

Max DC Output Current: 0.75A (standard for most BG10 series).

Understanding the Voltage Output

Brake rectifiers are used to match your factory's AC power to the specific DC coil inside the motor brake. For a bridge rectifier like the BG10. the output voltage is calculated as:

$$V_{DC} = frac{V_{AC}}{1.1}$$

Common examples:

230V AC Input 3$rightarrow$ produces approximately 205V DC (standard for 205V coils).4

115V AC Input $rightarrow$ produces approximately 103V DC (standard for 103V coils).

Wiring Guide (Typical 6-Pole)

While you should always check the diagram printed on the side of the unit, the standard 6-terminal layout for Lenze/Intorq rectifiers is:

Terminals 1 & 2: AC Input (from the motor mains or separate supply).

Terminals 3 & 4: DC Output to the Brake Coil.

Terminals 5 & 6: External Switching / Bridge (used if you want to accelerate the brake engagement time by switching on the DC side).

Signs of Failure

Brake won't release: The motor hums but the shaft won't turn (rectifier is not outputting DC).

Blown fuses: A short circuit inside the rectifier diodes will trip the motor starter or fuse immediately.

Overheating: Visible charring or a "burnt electronics" smell inside the terminal box.

Safety Warning: Always ensure power is disconnected before opening the terminal box. Brake circuits often retain a charge for a few seconds even after power is cut