The DOLD BA9040.12/010/60 3AC 50/60Hz 400V Asymmetry and Phase Sequence Relay (German: Asymmetrierelais) is a high-grade electrical protective component belonging to the prestigious VARIMETER series, engineered and manufactured by E. DOLD & SÖHNE GmbH & Co. KG in Germany. In modern industrial production environments, voltage unbalance between phases across three-phase mains supplies frequently occurs due to asymmetrical single-phase load distribution or transmission grid line disturbances. Even a marginal phase asymmetry of a few percent can induce severe reverse-sequence currents within electric motors, resulting in intense localized thermal dissipation, accelerated insulation degradation of stator windings, diminished mechanical torque, and catastrophic motor burnout.

The DOLD BA9040.12/010/60 series is purpose-built to shield critical electric motors and sensitive loads against these severe electrical irregularities. It continuously monitors the symmetry of phase angles and voltage amplitudes across 400V AC three-phase networks. The device seamlessly integrates three vital surveillance functions: precise detection of voltage unbalance exceeding preset tolerance levels, immediate recognition of total phase loss (even under regenerated feedback voltages induced by running induction motors), and verification of correct phase rotation sequence to prevent machinery from operating in reverse direction and inflicting mechanical drive damage.

Key engineering highlights of the BA9040.12/010/60 configuration:
- Contact Configuration ".12": Features 2 independent changeover contacts (2 C/O) with high switching capacity, allowing simultaneous isolation of the main contactor coil circuit and transmission of telemetry alarm signals to central PLCs or external visual/acoustic annunciators.
- Variant Suffix "/010": Integrates an adjustable response/release time delay potentiometer (typically 0.5 to 5 seconds), effectively filtering out nuisance tripping caused by transient voltage dips during heavy motor starting sequences.
- Variant Suffix "/60": Denotes an optimized 50/60Hz multi-frequency capability with enhanced electromagnetic interference (EMI) immunity, guaranteeing stable operation in volatile power network environments.

Housed within an industrial-grade, flame-retardant thermoplastic enclosure with a 45 mm module width, the unit snaps securely onto standard 35mm DIN-rails. Dual front diagnostic LEDs provide instantaneous visual feedback regarding operational health and detected grid faults, facilitating rapid on-site troubleshooting. Certified under stringent international safety standards including IEC/EN 60255 and DIN VDE 0435, the DOLD BA9040.12/010/60 is an indispensable asset for industrial pumping facilities, heavy air compressors, ventilation blowers, port cranes, and continuous automated production lines worldwide.

• Manufacturer: DOLD (E. DOLD & SÖHNE GmbH & Co. KG)
• Country of Origin: Germany
• Product Series: VARIMETER BA 9040
• Full Model Code: BA9040.12/010/60 3AC 50/60HZ 400V
• Technical Category: Voltage Asymmetry and Phase Sequence Relay (Asymmetrierelais)
• Nominal Measuring Voltage (UN): 3AC 400 V
• Nominal Frequency: 50 / 60 Hz
• Monitoring Functions:
  - 3-Phase voltage asymmetry / unbalance monitoring
  - Complete phase failure detection (even with motor regeneration)
  - Phase sequence verification
• Output Contact Arrangement: 2 Changeover contacts (2 C/O)
• Switching Capacity: AC-15: 3A / AC 230V; DC-13: 2A / DC 24V (according to IEC/EN 60947-5-1)
• Asymmetry Setting Range: Adjustable threshold limits via rotary dial (typically 5% to 15%)
• Time Delay Adjustment: Adjustable response time (0.5 ... 5 seconds) via front-panel potentiometer
• Visual Diagnostics: Dual LED indicators for normal operational status and phase fault conditions
• Module Dimensions (W x H x D): 45 x 74 x 133 mm
• Mounting Architecture: Snap-on mounting for standard 35 mm DIN-rail (IEC/EN 60715)
• Terminal Architecture: Vibration-proof box clamp screw terminals for secure industrial cabling
• Protection Degree: Housing IP40, Terminals IP20 (according to IEC/EN 60529)
• Operating Ambient Temperature: -20°C to +60°C
• Compliant Safety Standards: IEC/EN 60255, IEC/EN 60947-5-1, DIN VDE 0435, CE
• Typical Applications: Motor control centers (MCC), water pumps, industrial air compressors, exhaust fans, cranes, and automated conveyor lines