VFD panels
- Drives: ABB ACS580 / ACS880, Siemens G120, Schneider ATV600 / ATV900, Inovance / Chint, low voltage 0.75–500 kW
- Cooling: dedicated duct per drive, bottom intake and top exhaust, in-cabinet air conditioner or heat exchanger where required
- Harmonics: line reactor or EMC filter sized to power and grid conditions; DC reactor option for multiple drives in parallel
- Wiring: shielded cable on drive outputs with shield grounded at both ends; control and power wiring in separate wireways and layers
- Testing: no-load and on-load commissioning of every drive, parameters set to motor nameplate and process data, delivered with the panel
Specifications
The table below covers 80% of factory distribution room cases. Anything outside it we can still build — those are engineered items, quoted separately, with an indicative price the same day.
| Type | Floor-standing VFD panel / wall-mounted VFD box, single drive or multiple drives in parallel |
|---|---|
| Standard sizes (W×D×H) | Single unit 600×600×1800 / 800×600×2000 mm; multiple drives add width per unit, depth up to 800 mm |
| Enclosure construction | 2.0 mm cold-rolled carbon steel, bent and welded, reinforced at the drive mounting area |
| Surface treatment | Degrease → derust → phosphating → electrostatic powder coating 60–80 μm, baked at 200℃ |
| Cooling method | Bottom intake + top exhaust (with filters); in-cabinet air conditioner / heat exchanger optional for dusty or high-temperature environments |
| IP rating | IP54 standard / IP65 optional; filter media at cooling openings with access panel for service |
| Installation | Floor mounting; mount drives at least ≥300 mm above the cabinet bottom to ensure intake airflow |
| Maintenance access design | ≥400 mm clear space in front of the VFD; terminal blocks and breakers positioned so they can be serviced without removing the VFD |
| Suitable power | Low voltage, 0.75–500 kW (single unit); higher power available via multiple units in parallel or a medium voltage solution |
|---|---|
| Input voltage | AC 380V / 400V, 50 Hz, three-phase |
| VFD brand | ABB ACS580 / ACS880, Siemens G120, Schneider ATV600 / ATV900, Inovance / Chint |
| Control method | V/F control, sensorless vector control, closed-loop vector control (with encoder) |
| Speed control range | Typically 1:50 (V/F); over 1:1000 under vector control, depending on load |
| Harmonic mitigation | Line reactors sized to the power rating (2%–4% reactance) or EMC filters; for multiple units in parallel, DC reactors or centralized mitigation recommended |
| Braking and protection | Optional braking unit / braking resistor; includes overcurrent, overvoltage, undervoltage, overtemperature, phase loss and ground fault protection |
| Communication | Modbus RTU / Profinet / EtherNet/IP; can connect to a supervisory system or PLC |
| Single pump, single drive speed control | VFD + breaker + local control, closed-loop speed control based on pressure or flow signal |
|---|---|
| One drive, multiple pumps with rotation | One VFD controls multiple pumps (cycled soft start), with automatic rotation based on run hours |
| Multiple drives in a shared parallel cabinet | Multiple VFDs in parallel in one cabinet, sharing the incoming supply with individual outgoing circuits, each driving one motor |
| PLC-linked control scheme | PLC issues the frequency reference and start/stop commands centrally; the VFD only drives, all logic managed in the PLC |
| Supervisory control scheme | VFDs connect to the supervisory system via communication, allowing remote parameter read/write and trending of operating curves |
| Retrofit of existing equipment | Existing motor and contactor control retained; a VFD panel is inserted for speed control and soft start, with automatic bypass on shutdown |
| Reference standards | GB/T 7251.1 / IEC 61439-1 (assemblies); GB 12668.3 (EMC for adjustable-speed electrical drive systems) |
|---|---|
| Clearance & creepage | Meets pollution degree 3 and overvoltage category III requirements |
| Insulation resistance | ≥1 MΩ (500V megohmmeter, measured with the VFD disconnected) |
| Power frequency withstand voltage | Main circuit 2500V / 1 min, control circuit 1500V / 1 min |
| Temperature rise inside the cabinet | Under operating conditions, cabinet internal temperature should be ≤50°C; above this, an upgraded cooling solution is required |
| Routine tests (every unit) | Circuit checks, insulation and withstand voltage, ventilation check, no-load run, setup per motor parameters and loaded trial run |
| Documents with shipment | Electrical schematic, terminal list, VFD parameter table, BOM with brand and model, test report, factory photos |
Five steps to specify your run
A configuration summary is generated as you go. It travels with your inquiry, saving a round of confirmation.
Build details
Systems have been in service for decades, and the failure points are always the same few: poor busbar contact, water ingress at the door seal, high temperature rise in the correction cabinet, and mis-phased outgoing feeders. The six hard rules below are written for exactly these points — every cabinet can be traced to them.
VFD heat is exhausted separately
The VFD is the largest heat source inside the cabinet. We route air in at the cabinet bottom and out at the top to form an isolated duct, so hot air no longer circulates inside the cabinet and the ambient temperature for the remaining components drops.
Bottom air intake clearance
Leave at least 300 mm between the VFD and the cabinet bottom, and 400 mm of service clearance in front. These dimensions are fixed on the assembly drawing — if the cabinet ends up installed in a dead corner on site, that is not our service problem.
Ground the output shield at both ends
Use shielded cable for the VFD output, with the shield grounded at both the VFD end and the motor end — this is the opposite of single-end grounding for analog signals, so do not mix them up.
Separate control and power wiring
Route setpoint signals, communication cables and power cables in different wire ducts, and cross them perpendicular wherever possible. Many "VFD interference on analog signals" problems trace back to wiring inside the cabinet.
Line reactor impedance
Select a line reactor with 2%–4% impedance according to VFD power rating to suppress harmonics, flatten commutation notches, and reduce VFD tripping when grid voltage fluctuates.
No-load and on-load runs, one pass each
Before shipment we run the panel at no load to check parameters and rotation direction, then run it on load using the customer's motor parameters. The parameter sheet ships with the cabinet, so the site team can enter the values and match them directly.
Photos & enclosure construction
Below are photos taken in our own shop — from the complete unit down to the internal busbars and secondary wiring. Every build detail can be checked item by item.
Image key: 01–05 are shop photos (the numbers match the shot list). The line drawing shows the front elevation of the enclosure; dimensions match the specification table above.
Where these cabinets go
These are the routine applications — we can talk scheme and configuration directly. For the industry view, see the industry pages.
Energy-saving retrofits for fans and pumps
Quadratic torque loads: shaft power drops with the cube of speed, so the energy savings are the most direct.
Constant pressure water supply and heating circulation
Closed-loop speed control from pressure or differential temperature signals, replacing valve throttling.
Belt conveyors and conveying lines
Soft start and soft stop, less mechanical shock, and speed synchronization across multiple units.
Air compressors and compressors
Constant pressure air supply control: less unloading time and a narrower pressure band.
Extruders and machine tool spindles
Vector control for constant torque speed regulation, matched to the process curve requirements.
Adding a VFD to existing equipment
Keep the original line-frequency circuit as a bypass, so production continues on line frequency if the VFD faults.
Commercial terms
Specification dated September 2026; quotations follow this.
| Drawings & design | Free |
| MOQ | 1 unit (5 or more recommended for production) |
| Production lead time | 15-25 days after drawing approval |
| on-time delivery | 98% |
| Warranty | 12 months |
| Loading port | Ningbo / Shanghai, China |
| Component brands | Schneider / ABB / Siemens / Chint |
| Factory visit & dispatch confirmation | Factory visits welcome; finished-cabinet photos and video before dispatch |
| Capacity | 5,800+ units / year |
Documents for your engineering team
Selection manual, outline dimensions and RFQ checklist — for the customer's electrical engineer. All three documents are being organized by product line; download links go live once complete.
Six questions procurement and electrical engineers ask most
How do I choose between a VFD panel and a soft starter cabinet?
It comes down to whether you need speed control. If you only need smooth starting and stopping with low starting current, a soft starter cabinet is enough and costs less. If you need continuous speed control to match the process — fans, pumps, extrusion, conveying — you need a VFD panel. The two can also work together: a VFD panel with bypass switches to line-frequency operation on fault.
Is a line reactor mandatory?
The higher the power, the more you need one. You can skip it for a single low-power unit on a grid with ample capacity. At 30 kW and above, with multiple units in parallel, or when precision equipment shares the same transformer, we recommend a line reactor with 2%–4% impedance — far fewer harmonics and trips.
How do you handle VFD heat dissipation?
By default, air enters at the bottom of the enclosure and exhausts at the top, with filters on both openings. For dusty, damp or high-ambient-temperature locations, we upgrade to an enclosure air conditioner or heat exchanger and seal the enclosure to IP54. Which option applies depends on the temperature and dust at the installation site — just tell us where it will be installed before we quote.
The motor is far away — do I need an output reactor?
Above 50 m of cable (shorter for shielded cable), we recommend an output reactor or dv/dt filter to limit the overvoltage reflected from the long cable and its impact on motor insulation. The output cable should also be shielded and grounded at both ends.
Can multiple VFDs go in one enclosure?
Yes, but recalculate heat dissipation based on the total heat load, and account for line reactors and internal compartmentalization. With many units, we recommend a separate airflow path for each VFD and a wider, deeper enclosure — don't let the heat pile up in the middle.
Can the VFD panel connect to our PLC or supervisory system?
Yes. Modbus RTU / Profinet / EtherNet/IP all work. We configure and test the communication parameters against the point list you provide before shipment; how your PLC program is configured on your side can be noted in the drawings and parameter sheet as well.
Other cabinet types in the same main circuit
Related products use color-block placeholders for now (product photos not yet complete; they will be replaced together). Internal links will be filled in once live URLs are confirmed.
Need to change speed control, or is the power bill chasing you?
Send us the motor power, load type and installation environment, and we will provide a free VFD panel configuration plan and energy-saving estimate · quote within 24 hours. Direct from the source factory, MOQ 1 unit, 15–25 day delivery, 1-year warranty.
ISO 9001:2015 · CE(LVD+EMC) · CQC · IP65
When you write, include: single-line diagram or primary scheme, switch room layout, load list, and component brand requirements. You do not need complete drawings — capacity and cabinet type are enough to start.