TRAFOTEK CHK0520 – Three‑Phase Line Choke for VFD Input Protection and Power Quality

The TRAFOTEK CHK0520 is a robust three‑phase line choke designed to sit on the AC side of variable frequency drives and other power electronics. From my experience, this type of inductor is typically installed to trim harmonics, tame inrush currents, and smooth line disturbances—helping drives run cooler and last longer. You might notice that when a choke like the CHK0520 is fitted upstream of a VFD, nuisance trips and DC‑link stress usually drop, especially on networks with stiff or noisy supply.

Company’s Order Placement Process and Guarantees

• Warranty: 365 days
• Delivery: In‑stock items typically ship in 1 week; not more than 1 month at the latest
• Payment: 50% advance payment; full payment prior to delivery
• Express Carriers: FedEx, UPS, DHL

Key Features

• Harmonic attenuation – Limits current distortion drawn by VFD rectifiers, improving system power quality in many cases.
• Inrush and surge damping – Reduces line transients and inrush, which typically helps prevent drive DC‑bus overvoltage trips.
• Improved EMC behavior – Cuts high‑frequency ripple entering the supply, supporting easier compliance with plant EMC policies.
• Thermal robustness – Heavy‑duty windings and core design for stable inductance under load and reliable operation in panels.
• Low audible noise design – Vacuum impregnation and tight winding geometry generally reduce buzz in 50/60 Hz applications.
• Open construction for panel mounting – Straightforward base mounting in standard electrical cabinets.

Technical Specifications

Application Fields

The CHK0520 suits most three‑phase industrial cabinets where a VFD or rectifier draws non‑linear current. Typical placements include:

• VFD input line reactors for pumps, fans, compressors, and HVAC AHUs
• Conveyors, packaging lines, and machine tools to stabilize plant voltage
• Elevators, cranes, and hoists where line dips or sags can trigger trips
• Front‑end smoothing for UPS/rectifier cabinets and test benches
• Renewables and ESS interfaces where grid harmonics need damping

Advantages & Value

• Reliability uplift – By reducing THD and inrush, the drive’s DC‑link capacitors are typically less stressed, extending service life.
• Compatibility – Works with mainstream VFD brands across 50/60 Hz grids; easy to fit inside standard IEC cabinets.
• Cost control – Lower chance of nuisance trips and fewer capacitor replacements usually cut maintenance costs.
• Power‑quality support – Helps sites meet internal PQ targets without jumping straight to an AFE or active filter.
• Straightforward sourcing – Passive magnetics are predictable on lead time and service, which seems to be what maintenance teams prefer.

Installation & Maintenance

• Cabinet and mounting – Install on a rigid baseplate inside a ventilated enclosure. Keep vertical airflow unobstructed; allow clearance above the core.
• Wiring – Route three‑phase leads with minimal loop area. Tighten to the torque recommended by the terminal manufacturer. From my experience, re‑torquing after first heat cycles helps.
• Thermal considerations – Place away from heat sources like braking resistors. Maintain ambient up to 40 °C for typical ratings.
• Safety – De‑energize and lockout/tagout before any work. Verify absence of voltage on all phases; residual magnetic fields dissipate quickly.
• Routine maintenance – Quarterly dust removal with dry air; check hot spots with an IR camera; annual torque check. If PQ issues arise, measure line THD and verify inductance with a suitable meter.

Supporting Components (commonly paired)

• Input EMI/EMC filter – For sites with strict emissions limits, an upstream three‑phase EMI filter complements the choke to curb conducted noise.
• dv/dt or sine‑wave output filter – Protects long motor cables and insulation; used on the VFD output side.
• Brake resistor assembly – If the drive frequently regenerates, a matched braking resistor stabilizes the DC‑bus and reduces trips.
• Surge protection (SPD) – Type 2/3 SPDs on the same panel help clamp external surges the choke doesn’t address.

Quality & Certifications

• CE compliant; RoHS compliant
• Manufactured under ISO 9001 quality management
• Seller warranty: 365 days