The DOLD BI 9023 Series Electronic Motor Brake Relay (German: Bremsgerät / English: DC Injection Braking Unit) is an engineered industrial drive safety and deceleration control instrument researched and manufactured by E. DOLD & SÖHNE GmbH & Co. KG in Germany. In modern industrial operations, machinery driven by induction motors featuring significant rotating mass—such as circular saw blades, centrifugal separation bowls, rolling mill rollers, press flywheels, and heavy grinding wheels—frequently continue coasting freely due to inertia for tens of seconds or even several minutes after mains disconnection. This prolonged coasting creates severe workplace injury risks for operating personnel, increases machine cycle changeover delays, and causes rapid mechanical degradation of conventional friction brake pads due to excessive frictional heat.

The DOLD BI 9023 series decisively solves these operational challenges by implementing electrodynamic deceleration via direct current injection (DC Injection Braking) into the stator windings of 3-phase squirrel cage induction motors. Immediately following the disconnection of the motor supply contactor, the BI 9023 unit triggers its integrated high-power thyristor semiconductors to inject a controlled direct current into the motor windings. This direct current instantly establishes a stationary, non-rotating magnetic field within the air gap. As the rotor continues turning through this stationary field, it produces a powerful counter-torque that rapidly, smoothly, and safely brings the machine to a standstill within seconds. Because the braking torque is generated purely through electromagnetic induction, mechanical friction is eliminated—producing no brake dust, generating zero squealing noise, and requiring no routine maintenance intervals compared to conventional electro-mechanical shoe or disc brakes.

With a high peak braking current capacity of up to 60A, the BI 9023 reliably controls medium to heavy-duty motor drives. The front panel features two independent potentiometers: one for adjusting the braking current intensity (Braking Current IB) and one for tuning the duration of the braking cycle (Braking Time tB). This allows commissioning engineers to fine-tune the deceleration rate, achieving short stopping times while protecting drive shafts, gearboxes, and belts from mechanical shock.

This comprehensive entry consolidates seven specialized configurations within the DOLD BI 9023 series:
1. BI9023 UH AC115V+AC230V+DC24V 60A (2AC 200-480V, 1-20s): Standard model supporting mains voltages across 2AC 200-480V, 1-20s braking time, and universal multi-voltage auxiliary supply (AC 115V / AC 230V / DC 24V).
2. BI9023 UH AC400V 60A (2AC 200-480V, 1-20s): Standard model configured for direct AC 400V auxiliary control supply.
3. BI9023/300 AC400V 60A (2AC 200-480V, 1-20s): Variant /300 optimized for high-frequency switching cycles with an AC 400V control supply.
4. BI9023/100 UH AC115V+230V+DC24V 60A (2AC 200-480V, 1-30s): Extended braking duration variant spanning 1-30 seconds with universal AC 115V/230V/DC 24V supply, tailored for high-inertia equipment (heavy flywheels, large centrifuges).
5. BI9023/100 UH AC400V 60A (2AC 200-480V, 1-30s): Extended 1-30 second braking duration model with an AC 400V control supply.
6. BI9023/200 UH AC400V 60A (2AC 200-480V, 1-30s): Advanced /200 variant with integrated safety interlocking circuitry and dedicated telemetry signaling outputs, 1-30s braking time, AC 400V supply.
7. BI9023 UH AC115V+AC230V+DC24V 60A (2AC 30-100V, 1-20s): Specialized low-voltage power model spanning 2AC 30-100V, 1-20s braking time, universal multi-voltage supply.

Housed in a rugged industrial modular enclosure for 35mm DIN-rail or mounting plate installation, the unit features heavy-duty screw terminals and front diagnostic LEDs for control power and active braking status. Certified under European machinery safety standards including EN ISO 13849-1, EN 60204-1, and EN 60947-4-2, the DOLD BI 9023 provides dependable, wear-free deceleration across industrial manufacturing facilities worldwide.

• Manufacturer: DOLD (E. DOLD & SÖHNE GmbH & Co. KG)
• Country of Origin: Germany
• Product Series: BI 9023
• Technical Category: Electronic DC Injection Motor Brake Unit (Bremsgerät)
• Maximum Rated Braking Current: 60 A
• Covered Models in this Entry:
  - BI9023 UH AC115V+AC230V+DC24V 60A (2AC 200-480V, 1-20s)
  - BI9023 UH AC400V 60A (2AC 200-480V, 1-20s)
  - BI9023/300 AC400V 60A (2AC 200-480V, 1-20s)
  - BI9023/100 UH AC115V+230V+DC24V 60A (2AC 200-480V, 1-30s)
  - BI9023/100 UH AC400V 60A (2AC 200-480V, 1-30s)
  - BI9023/200 UH AC400V 60A (2AC 200-480V, 1-30s)
  - BI9023 UH AC115V+AC230V+DC24V 60A (2AC 30-100V, 1-20s)
• Power Stage Operating Voltage (UN):
  - Standard voltage range: 2AC 200 ... 480 V ± 10%
  - Low-voltage range: 2AC 30 ... 100 V ± 10%
• Nominal Frequency: 50 / 60 Hz
• Auxiliary Control Voltage (UH):
  - Multi-voltage variants: AC 115 V / AC 230 V / DC 24 V (terminal selectable)
  - 400V variants: AC 400 V ± 10%
• Deceleration Principle: Controlled DC injection into motor stator windings (wear-free)
• Braking Current Adjustment (IB): Infinitely adjustable from 10% to 100% (up to 60A) via front potentiometer
• Braking Time Range (tB):
  - Standard and /300 models: 1 ... 20 seconds (adjustable via potentiometer)
  - Extended /100 and /200 models: 1 ... 30 seconds (adjustable via potentiometer)
• Duty Cycle: Optimized for industrial intermittent duty cycles
• Interlocking Control Outputs: Relay contacts for motor main contactor interlocking and safety circuits
• Visual Diagnostics: Front LEDs for auxiliary supply indication and active braking status
• Mounting Configuration: Snap-on mounting for standard 35 mm DIN-rail (IEC/EN 60715) or screw mounting
• Terminals: Heavy-duty industrial box clamp screw terminals engineered for 60A current carrying capacity
• Protection Rating: Housing IP40, Terminals IP20 (according to IEC/EN 60529)
• Ambient Operating Temperature: 0°C to +45°C
• Compliant Safety Standards: EN ISO 13849-1, EN 60204-1, EN 60947-4-2, CE
• Common Industrial Applications: Woodworking circular saws, band saws, planers, centrifuges, industrial mixers, grinders, textile machinery, and heavy conveyors