Basler UFOV 250A/260A protection module

Engineering Tip: If the excitation relay continues to engage, it may shield the underfrequency signal. It is necessary to check whether the excitation circuit is released after the frequency is normal.

Fault phenomenon 3: Failure to trip or excessive deviation of trip value during overvoltage

Inspection steps: ① Check whether the wiring of the circuit breaker coil power supply circuit (N and D terminals) is reliable; ② Check if the overvoltage potentiometer is damaged or drifting; ③ Test the resistance of the circuit breaker coil (normally conducting); ④ Replace modules or circuit breakers.

Common root causes: circuit breaker coil burnout or mechanical jamming, or failure of overvoltage triggering circuit inside the module.

Fault phenomenon 4: The circuit breaker repeatedly trips (especially during load shedding)

Analysis and handling: Firstly, eliminate serious faults such as external short circuits, and then adjust the overvoltage setting value appropriately to be higher than the transient peak value of load shedding. If it continues to recur, it may be considered to parallel RC absorption circuits at both ends of the circuit breaker coil (consult the manufacturer) to suppress interference.

Suggestions for spare parts management and replacement upgrade

1. Key spare parts list

Component Basler Part Number Function Description

Circuit board (UFOV 260A) 9 1051 00 100 60Hz module main control board

Circuit board (UFOV 250A) 9 1051 00 101 50Hz module main control board

Choke coil L1 BE 13693-002 input filtering

Choke coil L2 BE 08794-010 output filtering

Transformer T1 BE 14101-002 multi tap input transformer

Single pole circuit breaker 05390 50A @ 480Vac

Bipolar circuit breaker 05391 50A @ 480Vac (for A/F0 terminals)

2. Precautions for replacing old models

The underfrequency action point of the old model UFOV 250/260 (part number 9 0400 00 100/104) is below 10 Hz, and the terminal definitions are different (using 1, 2, 3, 4, 6). If replacing with a new model, it is necessary to rewire according to the terminal comparison table in the manual, especially by splitting the wiring on the original terminal 6 to terminals D and N.

The underfrequency action window of the new module is narrower (4-7 Hz), and in applications with a wider frequency adjustment range, the protection coordination needs to be re evaluated.

3. Lifespan and reliability

The module adopts industrial grade solid-state circuits, with no vulnerable mechanical components (except for circuit breakers), and regular checks on wiring tightness and cleanliness are sufficient. It is recommended to conduct a functional test every two years (including underfrequency and overvoltage action verification) to ensure the integrity of the protection logic.