Basler Electric BE1-59N – Solid‑State Ground Fault Relay (Style A5EE1KC0N0F)

The Basler Electric BE1-59N (style A5EE1KC0N0F) is a solid‑state protective relay that provides sensitive ground‑fault detection for generators, transformers, and large motors. It operates by measuring the neutral overvoltage (voltage displacement) that occurs during a phase‑to‑earth fault, offering a reliable and cost‑effective protection solution.

Detection Principle

During normal balanced operation, the neutral voltage is close to zero. When a ground fault occurs in the stator winding, the neutral point shifts, generating a zero‑sequence voltage. The BE1-59N continuously monitors this neutral voltage and trips when it exceeds a user‑adjustable pickup level. The relay includes a time‑delay function to coordinate with downstream devices and prevent nuisance tripping on transient disturbances.

• Voltage input: neutral VT input, 120/240 V AC nominal

• Pickup setting: 0.5–20% of rated neutral voltage

• Time delay: 0.1–10 seconds (adjustable)

• Accuracy: ±2% of setting

• Output contacts: 2 Form‑C relays, 5 A at 250 V AC

• Power supply: 120/240 V AC or 125/250 V DC

• LED indicators: power, alarm, and trip

• Mounting: panel draw‑out case

• Operating temperature: –20 °C to +65 °C

Applications

This relay is essential for protecting high‑impedance grounded generators and transformers from stator winding faults that may not produce sufficient current to operate conventional overcurrent relays. It is also used in industrial motor protection where ground‑fault sensitivity is required. The BE1-59N is particularly useful for machines that operate in isolated or resistance‑grounded systems.

Installation and Calibration

Mounting is via a standard panel cutout with front‑accessible controls. All connections are made through screw terminals. The pickup level and time delay are set using potentiometers and DIP switches, with calibration marks for repeatable settings. A test jack allows verification without live neutral voltage.

Reliability and Compliance

Built with Basler's robust solid‑state technology, the BE1-59N is immune to transients and electrical noise. It complies with IEEE C37.90 and IEC 60255 standards, ensuring consistent performance in protective relay applications.

In summary, the Basler Electric BE1‑59N ground fault relay provides sensitive, adjustable neutral overvoltage protection, safeguarding critical power equipment from earth‑fault damage.