Common troubleshooting and countermeasures
Possible causes and solutions for the phenomenon
When the large motor starts, the voltage still drops severely, and CBS has no response. ① The action point is set too high (the drop voltage has not reached the action point); ② CT selection is too small, resulting in insufficient output power; ③ CT polarity is reversed and adjusted to a low operating point (such as from 85V to 75V); Verify whether the CT ratio meets the short-circuit current requirements; Check the CT secondary current waveform with an oscilloscope
CBS frequently malfunctions (starting with normal load fluctuations), the action point is set too low, and the action point should be appropriately raised near the operating voltage (such as from 75V to 85V), and the amplitude of load fluctuations should be checked
CBS does not exit for a long time after startup, resulting in the failure of over excitation return hysteresis setting or slow voltage recovery. Check whether the actual value of PT secondary voltage has truly recovered to above hysteresis; If the return difference is insufficient, you can consult the manufacturer to see if it is adjustable (this model is fixed)
The output DC voltage cannot reach the set value, and the CT capacity is insufficient or the output limiting potentiometer is not adjusted to the maximum. Verify the CT ratio to ensure that the short-circuit current is within the CT rated range; Rotate the 'Output Limit' clockwise needle to the end
If the device heats up severely and works continuously for too long (more than 10 seconds) or has poor heat dissipation, check whether it is caused by the motor starting time being too long, and consider adding starting current limiting measures; Ensure ventilation in the installation space
Comparison with PMG scheme and suggestions for replacement and upgrade
The traditional PMG scheme requires the addition of permanent magnet generators, PMG voltage regulators, and rectifier bridges on the generator shaft, which not only increases costs but also requires installation space and mechanical reliability. CBS 212A:
No mechanical modifications required, only through electrical connections, suitable for retrofitting old units.
Dynamic response is faster, as CT directly extracts energy without the inertia delay of PMG.
Lower cost, especially suitable for multiple units to share spare parts.
However, it should be noted that the boost energy of CBS 212A is limited by the magnitude of the short-circuit current. If the short-circuit ratio of the generator is low (such as<3 times), it may not be able to provide sufficient excitation current. At this time, a higher transformation ratio CT or an active magnetic assistance scheme should be considered. For systems with high short-circuit currents (such as near substations with large short-circuit capacity), it is necessary to limit the output amplitude of CBS to prevent excessive excitation.
When replacing similar devices that have been discontinued (such as early models of the Basler CBS 200 series), the wiring and installation dimensions of CBS 212A are basically compatible, and only the CT ratio and voltage gear need to be checked.
Regular maintenance and lifespan management
Periodic functional testing: Once a year, simulate voltage drop and check whether the action value and output current are normal.
CT circuit inspection: Regularly tighten the CT wiring terminals to prevent increased contact resistance from affecting energy harvesting efficiency.
Heat dissipation inspection: Clean the heat sink to ensure that the ambient temperature does not exceed 60 ° C.
Electrolytic capacitor lifespan: The internal filtering capacitor has a lifespan of about 10 years. If there is an increase in output ripple, you can contact the manufacturer to replace the capacitor component.
Selection Decision Process
Confirm the rated current and short-circuit factor of the generator (usually provided by the manufacturer).
Calculate 300% short-circuit current (600A if rated at 200A).
Select the corresponding CT model based on the system voltage (≤ 600V or ≤ 15kV) and short-circuit current range by referring to the table.
Select the rated voltage of the exciter and determine the output gear (60/120/220V).
Determine the operating point voltage (usually 70%~85% of the rated PT voltage).
Purchase one CBS 212A and two matching CTs.
