Allen‑Bradley 21T-LCL-CB5 LF2 LCL Capacitor Bank Kit Unit

Module Feature

21T-LCL-CB5 is a complete factory assembled LCL capacitor bank kit for Allen‑Bradley LF2 frame variable frequency drive, rated 520A.

It works as part of LCL harmonic filter assembly, suppresses PWM high-frequency harmonic emission, reduces grid distortion and motor cable dv/dt stress. Matched to LF2 drive power frame, pre-wired capacitor group with internal discharge resistor and over-temperature protection. Metal enclosed structure, EMC industrial grade, suitable for long motor cable application. Widely stocked as maintenance spare for large fan, compressor and process MCC drive cabinet.

Working principle

The LCL filter capacitor bank cooperates with series inductor to form low-pass filter network. It shunts high-frequency harmonic current generated by drive IGBT switching, smooths output voltage waveform and reduces reflected wave on long motor cables. Discharge resistors drain residual voltage after power off for safety. Built-in thermal protection cuts off capacitor loop when overheating occurs.

Onboard componentsPolypropylene film power capacitor group, discharge resistance, temperature thermal switch, internal wiring busbar, terminal block, metal enclosure and status thermal indicator.

LED indicatorsThermal alarm indicator shows over-temperature fault status.

Hardware self‑diagnosisBuilt-in thermal supervision detects overheat of capacitor bank. Regular inspection checks capacitance value, insulation resistance and terminal temperature rise.

Programming softwareNot applicable, passive filter assembly.

Electrical & Process Parameters

Model:21T-LCL-CB5 Brand:Allen‑Bradley (Rockwell Automation) Device type:LF2 LCL capacitor bank kit Function:Harmonic filtering, dv/dt suppression and power factor improvement for LF2 VFD

Mechanical & Structure

Mounting:Installed inside MCC compartment or adjacent to LF2 drive Protection class:IP20 Housing:Metal enclosed filter assembly

Environmental

Operating temperature:-5℃ ~ +50℃ Storage temperature:-40℃ ~ +85℃ Ambient humidity:5~95% non‑condensing

Certification:CE, UL, IEC61800 Status:Original Rockwell drive filter spare

Installation

Isolate upstream power and confirm capacitor fully discharged before replacement. Match LF2 frame drive, check phase wiring, verify thermal alarm wiring, test temperature rise and harmonic suppression after commissioning.

InterfaceThree-phase power terminal block, thermal alarm signal terminal.

Diagnostic

Capacitance drift: Capacitor aging, long service life. Over-temperature alarm: Poor ventilation, overloaded harmonic current. Insulation fault: Moisture ingress, terminal contamination.

Product Brief21T-LCL-CB5 capacitor bank kit, Rockwell LF2 520A LCL harmonic filter spare for large variable frequency drive MCC cabinet replacement.