Find a VFD part number from motor HP, kW, or full-load amps

How It Works

1. Enter the motor size

   Fill in any one of horsepower, kilowatts, or full-load amps. All three are optional individually but at least one is required, and the tool will not guess a motor size. If you enter both HP and kW, the kW figure is used as the motor size because it needs no conversion. Full-load amps take priority over both when present.

2. Set the supply

   Pick 3-phase or 1-phase and enter the supply voltage. The picker offers 120, 208, 230, 240, 400, 415, 460, 480, 575, 600, and 690 V. Voltage decides the band that gets searched: 100 to 127 V, 200 to 240 V, 380 to 480 V, or 500 to 690 V.

3. Choose the duty class

   Normal duty covers pumps and fans. Heavy duty covers conveyors, crushers, hoists, and positive-displacement pumps. Leaving it on Not sure yet reads every rating at its normal-duty figure and says so, which on a constant-torque load can leave the answer one frame too small.

4. Read the closest match per brand

   The first table gives one row per brand: the smallest rating in the data that covers what you entered. Underneath, Other sizes in range lists the next size up and the other families in the same envelope, which is where you look for headroom or for a family your account actually carries.

5. Check the code completeness column

   Each row says whether its string is a complete catalog number or a rating code. A rating code is the segment that describes the rating and nothing else. The row explains what a full ordering string still needs, and that is the part you finish with the manufacturer or your distributor.

6. Read the flags before you quote anything

   Per-row flags cover voltage near-misses, heavy-duty ratings that were read at the normal-duty column, legacy or superseded lines, undersized fall-back candidates, and motor-label mismatches. Result-level notes cover the dataset gaps. None of it is decoration; a flagged row is a row that needs a second look.

7. Copy the RFQ block or export

   The RFQ panel builds a plain-text request for quote with the supply, motor data, duty, candidate part numbers, and the completeness labels, ready for the clipboard or for a mailto draft you address yourself. Nothing is sent anywhere. CSV, branded PDF, and a shareable URL that reopens the same query are also available.

Built For

• Sizing a replacement drive for a 7.5 HP 480 V three-phase fan motor and wanting the actual PowerFlex catalog number rather than an amp figure to hand to purchasing.
• Cross-shopping a conveyor drive on heavy duty when the plant standard is ABB but the ABB lead time is long, and needing to see which Yaskawa and Danfoss ratings sit in the same envelope.
• Working from a motor nameplate that reads 25 A full-load amps with no legible horsepower, and needing the drives whose rated output current actually meets that current at 480 V.
• Checking whether a 400 V class drive quoted by a supplier is rated for a 480 V plant supply, which is where the published range matters more than the class label.
• Building a spare-parts list for a line running mixed brands and wanting one shortlist per brand at the same motor rating, with the differences shown as numbers.
• Pricing an upgrade where the existing drive is a legacy line and the current equivalent needs to be identified before the quote goes out.
• Preparing a request for quote for a distributor who wants the model string, the motor data, the duty, and the quantity in one block instead of a phone call.

Features & Capabilities

Amps beat horsepower when you have them

Full-load amps set the selection basis. The rated output current at the chosen duty must meet the entered amps, and candidates are ordered by least excess current so the closest correct size leads. HP or kW entered alongside becomes a motor-label cross-check that raises a flag when the drive rating and the entered motor size disagree by more than a quarter.

Four brands matched independently

Every brand is searched on its own against the same phase, voltage band, and duty, so filtering to one brand never changes the rows you would have seen with all four. Up to three rows per brand are shown, and a diversity slot keeps a next-size-up option on the list when several families publish the identical rating.

Code completeness stated, never implied

The model string on each row comes verbatim from the rating data. It is never assembled and never edited. A row is labelled a complete catalog number only when it matches a published Rockwell catalog shape with no open segment; every other row is labelled a rating code and carries one sentence on what the full ordering string still needs.

Data gaps surfaced, not papered over

Where the source publishes one duty column instead of two, or where rows were dropped at bake time rather than shipped with a suspect key, the result says so. A brand with no drive in your phase and voltage band gets a gap card naming the bands it does hold, instead of a forced nearest match.

Worked example rendered without touching the tool

The page shows one fully worked case computed by running the finder itself, so it can never drift from what the tool returns. A 7.5 HP motor on a 480 V three-phase supply at normal duty returns the PowerFlex 525 catalog number 25B-D013N104: 13 A normal duty, 5.5 kW, 7.5 HP, frame C, published range 380 to 480 V.

Request for quote without a lead form

The RFQ panel assembles a plain-text block carrying manufacturer, model string, completeness label, quantity, need-by date, and the spec summary the finder just produced. It goes to the clipboard, or into a mail draft with an empty recipient line that you address yourself. No email address is collected, no recipient is suggested, and nothing leaves the browser.

What each brand publishes: the cross-shop matrix

Assumptions

• Rating rows come from the audited ToolGrit VFD cross-reference dataset, baked from the four shipped brand decoders. The engine and the data are copied into this app verbatim with a provenance header and a test that re-checks the copy on every run.
• The model string on every row is verbatim from that dataset. It is never assembled, never edited, and never completed by inference.
• Full-load amps, when entered, are the selection basis and the drive rated output current at the chosen duty must meet them. Horsepower or kilowatts entered alongside is a cross-check only.
• An entered horsepower is snapped down onto the nearest published motor step when the gap is inside 8 percent, which reproduces the standard IEC and NEMA equivalences (7.5 HP with 5.5 kW, 15 HP with 11 kW, 25 HP with 18.5 kW, 50 HP with 37 kW) without inventing a value.
• A heavy-duty request reads the published heavy-duty current where the brand has one. Where it does not, the normal-duty figure is used and the row is marked heavy-duty unverified.
• A drive is treated as covering your supply only when the supply voltage falls inside the published range recorded for that row. A near-miss is shown with a flag, never silently treated as a fit.
• Input limits: 0.1 to 3000 HP, 0.1 to 2500 kW, 0.1 to 5000 A, and 90 to 700 V. Anything outside those is refused with a reason rather than clipped.
• PowerFlex ratings in this dataset were recovered from the shipped PowerFlex decoder bundle, which publishes the normal-duty column only.
• Danfoss rows carry one continuous rating. The second column in the Danfoss source is an intermittent-overload peak, not a continuous heavy-duty rating, so it is not used.

Limitations

• It does not check physical fit: footprint, depth, mounting pattern, terminal layout, and cable entry are not modelled.
• It does not pick enclosure, EMC filter, keypad, fieldbus, I/O, or safety options. Those are exactly the segments a rating code does not carry, which is why three of the four brands return rating codes rather than orderable part numbers.
• It does not verify functional safety level (STO category, SIL), agency approvals, or hazardous-location listings.
• It does not apply ambient temperature, altitude, or switching-frequency derating.
• It does not do the input-side work: branch-circuit protection, line reactors, harmonic limits, and whether the existing feeder and starter wiring are sized for the drive you pick are all outside its scope.
• It does not size a three-phase drive fed from a single-phase supply. The single-phase rows it returns are drives the manufacturer publishes for a single-phase supply. Running a three-phase-input drive on single-phase power needs its own derating pass.
• It does not know price, stock, lead time, or which distributor carries a line.
• Coverage is 20 families across four brands, not every drive those manufacturers sell. A brand with nothing in your phase and voltage band returns a gap card naming the bands it does hold, and no substitute is invented.
• Heavy-duty answers for PowerFlex and Danfoss are matched on the continuous rating because that is all this dataset holds for those brands. On a constant-torque load the catalog heavy-duty size is usually a frame or two smaller than the continuous figure, so confirm it in the catalog.

References

1. ABB ACS880-01 hardware manual 3AUA0000078093 Rev V, IEC ratings from page 234 and UL ratings from page 238.
2. ABB ACS580-01 hardware manual 3AXD50000044794 Rev G, IEC ratings pages 292 to 295 and UL ratings pages 298 to 301, cross-checked against the ACS580 catalog Rev M pages 27 to 33.
3. ABB ACS480 hardware manual EN_ACS480_HW_F_A5 Rev F, IEC ratings pages 131 to 133 and UL ratings pages 132 to 135.
4. ABB ACS380 technical catalog ACS380-PHTC01U-EN Rev K pages 9 to 14.
5. ABB ACS180 hardware manual EN_ACS180_HW_D Rev D, IEC ratings pages 97 to 100 and UL ratings page 100.
6. ABB ACS355 catalog 3AUA0000068569 Rev H page 10, with the ACS355 user manual 3AUA0000066143 Rev E page 376.
7. Yaskawa GA800 technical reference SIEPC71061737, drive rating tables.
8. Yaskawa GA500 technical reference SIEPC71061752, drive rating tables.
9. Yaskawa A1000 technical manual SIEPC71061641 and V1000 technical manual SIEPC71060618, drive rating tables.
10. Danfoss VLT AutomationDrive FC 301 and FC 302 design guide AJ286655760917en-002201, Tables 25 to 37.
11. Danfoss VLT Micro Drive FC 51 design guide AJ361178983102en-000401, rating tables.
12. Danfoss VLT HVAC Drive FC 102 and VLT AQUA Drive FC 202 design guides, Tables 5, 6, 163, and 164, normal-overload continuous output current.
13. Rockwell Automation PowerFlex 520-series and 750-series rating data, recovered from the shipped ToolGrit PowerFlex decoder bundle (normal-duty column only).
14. Rockwell Automation product page for catalog number 25B-D013N104 (7.5 HP / 5.5 kW, 380 to 480 V, 13 A), used as the worked-example verification anchor.

Frequently Asked Questions