How to read a VFD nameplate

Start with the complete type designation, including every dash, letter, digit, and option suffix. The useful rule is simple: split a code only where the manufacturer splits it, and keep the exact family manual beside your notes. A pattern learned from one drive family is not a decoder for another.

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The family manual controls the decoding. An undefined suffix stays in the copied reference but does not acquire a guessed meaning.

Rockwell gives a precise example for the PowerFlex 400. The catalog-number description on page 107 of publication 22C-UM001K-EN-E labels the positions in 22C-B024N103 as drive, voltage rating, rating, enclosure, HIM, emission class, and communication slot. On the same page, 22C-D038A103 appears in the 480 V, 50/60 Hz, three-phase table as an 18.5 kW or 25 hp normal-duty drive with 38 A output ratings and frame D. That is the right 22C source; the PowerFlex 4 manual numbered 22A-UM001 is for a different family.

Lenze needs a firmer boundary. Its official page identifies 8200 vector as a modular frequency-inverter range, but the page does not mention E82EV751K4C200 or define the E82EV, 751, K4C, or C200 blocks. Copy E82EV751K4C200 in full if that is what the unit shows, and leave its block meanings unexpanded until a family-specific Lenze type-code table supports them.

ABB shows why the printed characters are not always the rated decimal value. The ACS580-01 type key on page 57 says ACS580 is the series, 01 is the basic wall-mounted configuration, the size block points to the rating tables, and 4 denotes the 380 to 480 V voltage class. In the IEC table on page 294, size 09A5-4 has nominal input and output current of 9.4 A at 400 V, not 9.5 A. Read 09A5 as the published size code and record 9.4 A as the table value for that stated condition.

The practical result is a two-column note: exact characters on the left, manufacturer-supported meaning on the right. When a source defines only part of the string, keep the remaining characters intact and mark their meaning unknown. That record is more useful than a confident expansion assembled from seller listings or a nearby product family.

After the type designation, transcribe each rating with its printed label and unit. Keep input voltage, phase count, frequency, and input current apart from output voltage, current, frequency, and power. Do not combine them into a single summary number, because the manufacturer may define several output-current ratings for different duties and temperatures.

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Symbols and conditions travel with the numbers. The diagram organizes a document check; it does not prescribe settings or commissioning work.

The ACS580-01 manual makes that distinction explicit. Its label section on pages 54 to 55 says the type designation label includes IEC and UL ratings, the type designation, and the serial number. In the definitions following the ratings tables on page 297, I1 is nominal input current, I2 is maximum continuous output current with no overload, ILd is the continuous output current for the stated light-duty overload cycle, and IHd is the corresponding heavy-duty value.

For ACS580-01-09A5-4 at 400 V, page 294 lists I1 and I2 as 9.4 A, Imax as 13.0 A, ILd as 8.9 A, and IHd as 7.2 A. Those numbers are not interchangeable. The manual defines the usual light-duty allowance as 10 percent for one minute every ten minutes and the usual heavy-duty allowance as 50 percent for one minute every ten minutes, while also printing model-specific exceptions. Record the symbol, value, temperature, and duty wording together rather than calling one value simply the overload rating.

Sizing is also family-specific. On page 304, ABB bases ACS580 sizing on rated motor current, voltage, and power, then notes that derating can apply above the stated ambient temperature. That supports a document comparison, not a universal rule that current alone selects a drive. Put the motor values beside the drive values and send any unresolved duty or derating condition into the separate sizing review.

Keep the type designation, serial number, hardware identifiers, and firmware version as separate fields because they may come from different places. ABB's ACS580-01 hardware manual says the physical type label carries the type designation and serial number; it does not say that label carries the firmware version. Rockwell's PowerFlex 400 release notes instead point to the Control SW Ver value and supported software or display views for firmware identification.

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A version value selects applicable documentation. It does not by itself establish electrical, physical, option, or application fit.

That difference changes how you cite the record. A photograph can support a printed serial number, but a firmware value needs a dated screenshot, service record, or other manufacturer-defined readout. If safe, authorized evidence is not already available, write firmware not captured. Do not infer firmware from the catalog number, production date, or the manual that happened to be found first.

Firmware matters at the documentation boundary. Rockwell's version 7.01 release notes list new and updated parameters on pages 11 and 12, so the version tells a reviewer which release notes describe that drive's control software. ABB likewise states in its firmware manual that the manual applies to a named control-program version and that different ACS580 frame and control-unit constructions use different firmware lines.

None of those identifiers proves that a replacement will fit. They narrow the documents and release notes that apply; physical dimensions, supply, motor ratings, duty, options, communications, parameters, and the machine application still need their own sourced comparison. Record type and firmware as separate matched fields, not as a drop-in verdict.

Use an existing maintenance photograph or a safe, authorized view of the external label whenever possible. This guide does not ask you to open an energized cabinet, remove covers, defeat guarding, or reach around live equipment for a better angle. If the label cannot be viewed safely, record that limit and leave access to qualified personnel following the site procedure and manufacturer instructions.

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Capture begins only from a safe, authorized view. The flow contains no energized inspection, isolation, wiring, or commissioning procedure.

When the equipment is already in a safe state under that procedure, take one frame that shows which drive the label belongs to and another that keeps the small text legible. If an accessible option module has its own label, photograph that label separately instead of appending its characters to the main drive string. If a replacement label is present, record it as a replacement rather than silently treating it as the original plate.

Copy the type designation in one piece, character for character, next to the image. Then transcribe the labeled rating values and the serial number without expanding any code from memory. The image and text do different jobs: the image preserves layout and characters, while the transcription makes the record searchable and easy to compare.

Check focus, glare, and cropped edges before the safe access window ends. If a line is unreadable, mark that line unreadable and keep the original image. A visible uncertainty can be resolved later against another source; an invented character can send every later search toward the wrong product.

A usable record separates observation from interpretation. Write the exact type designation, each labeled rating, serial number, image filename, equipment location, and capture date as observations. Put every decoded block or rating definition beside the manufacturer document title, publication number, revision, section, and page that supports it.

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The pack preserves provenance and unknowns. It supports a later decision but does not diagnose a fault or approve a replacement.

Add only the machine context that was actually observed or attributed. Which motor tag was associated with the drive, where the unit was mounted, and what an existing maintenance record reported can help a reviewer, but each line should say who or what supplied it and when. Context is not proof that the drive was correctly sized or that the reported symptom came from the drive.

Conflicts stay visible. For ACS580-01-09A5-4, the characters 09A5 and the 9.4 A IEC table value belong on separate lines, with the manual page attached to the latter. For E82EV751K4C200, the full observed string can be strong identity evidence even while the suffix meanings remain unknown.

The finished pack supports later sizing and sourcing conversations without deciding them in advance. A reviewer can see what was printed, what came from a manufacturer source, what came from a person or machine record, and what remains unknown. That boundary is what makes the evidence reusable instead of merely persuasive.

• Copy the complete type designation and decode only the blocks defined by the exact family manual.
• Keep rating symbols, values, units, duty, temperature, and voltage conditions together.
• Record firmware from a manufacturer-defined, safely obtained source, not from the catalog number or a guess.
• Preserve conflicts and unknown suffixes in the evidence pack instead of silently resolving them.

• the drives and VFD hub
• why reference suffixes matter
• the replacement sizing checklist