Basler Electric BE1‑60 Voltage Balance Relay

The Basler Electric BE1‑60 is a solid‑state voltage balance relay that monitors the voltage imbalance between the three phases of a power system. It is used to protect three‑phase induction motors and generators from the damaging effects of negative‑sequence currents caused by unbalanced supply voltages. Unbalance leads to rotor overheating, vibration, and reduced machine life. The relay trips when the voltage imbalance exceeds a preset level for a selected time delay.

Operating Principle

The relay measures the positive‑sequence and negative‑sequence components of the three‑phase voltage. The ratio of negative‑sequence to positive‑sequence voltage (V2/V1) is compared to an adjustable setpoint (typically 2‑15%). When the ratio exceeds the setpoint for a time delay (1‑30 seconds), the relay operates. A built‑in filter prevents nuisance tripping due to transient unbalance during motor starting or fault clearing.

Adjustable Settings

Front‑panel potentiometers allow adjustment of the unbalance pickup level and time delay. The relay also includes a dropout ratio of approximately 95% to avoid chattering. An LED indicator shows the presence of unbalance, and a target indicator records trip events. A reset pushbutton clears the target and resets the relay.

Technical Specifications

Input voltage: 100‑480 VAC, 50/60 Hz. Pickup range: 2‑15% unbalance (adjustable). Time delay: 1‑30 seconds. Accuracy: ±2% of setting. Output contacts: 1 Form C (SPDT), rated 5 A at 250 VAC. Power supply: 24‑250 VDC or 120‑240 VAC. Operating temperature: –20°C to +65°C. Enclosure: metal, panel‑mount. Meets IEEE C37.90.

Applications

The BE1‑60 is used to protect large motors, generators, and transformers from voltage unbalance. It is commonly installed in motor control centers, generator control panels, and industrial power distribution systems. It can also be used as a supervisory relay for alarm or load shedding.

Installation and Commissioning

Mount the relay in a standard cutout. Connect the three‑phase voltage inputs. Set the unbalance pickup and time delay based on the equipment manufacturer’s recommendations. Commissioning involves injecting unbalanced voltages to verify trip accuracy. The relay includes a test jack for signal injection.

Reliability and Quality

Basler Electric’s BE1‑60 is built with solid‑state technology and conformal coating for durability. It is factory calibrated and tested. The relay requires minimal maintenance and has a long service life.

Conclusion

The Basler Electric BE1‑60 voltage balance relay (C1F A1P D0C3F) is a reliable and sensitive device for detecting and protecting against voltage unbalance. Its simple adjustment and rugged construction make it an excellent choice for motor and generator protection.