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VFD Replacement Cross Reference: Six Checks Before You Swap
A VFD replacement cross-reference matches a model number to a model number. It cannot tell you whether the replacement will fit your cabinet, drive your motor, or satisfy your safety circuit. That gap is where most swap-outs go wrong.
The table is not wrong. It is incomplete. A mapping tells you which product line succeeded which, and for a same-family transition it is often exactly right. It just cannot read your panel, your PLC program, or your motor nameplate.
This article covers the six checks to run before anything is ordered, what to record before the old drive comes off the panel, and the traps that make a named successor a poor replacement. If you are still specifying rather than replacing, start with how to choose a VFD, because that is a different problem with a different answer.
Key Takeaways
- A cross-reference matches models. It does not match output current, duty class, feedback, communications, safety functions, or mounting.
- One physical frame carries two current ratings. Schneider’s documentation states that when a drive is programmed for Heavy Duty, “the HP rating and current rating are decreased.”
- Lifecycle dates come in threes: end of production, end of spares, end of repair. The middle one decides when you must act.
- A replacement can be electrically compatible and still invalidate a UL listing. A CMCO option card fits Series 5 drives but does not itself comply with UL, CSA, or CE.
- A named successor may not cover your power range. Siemens is retiring the SINAMICS G180 and the G220 below it cannot serve every rating.
What a VFD Replacement Cross Reference Actually Tells You
Cross-reference is used loosely for two very different exercises, and they carry different levels of confidence.
Same-Brand Succession: the Reliable Case
When a manufacturer documents that its own line replaced an earlier one, that is the strongest cross reference available: it knows both drives and publishes the differences.
Schneider Electric’s FAQ on the Altivar 61 is a good example. It states the ATV61 “has been phased out of production in the US in 2016” and maps the replacements: the ATV630 in IP21 replaces the open-style ATV61H, the ATV650 in IP55 replaces the Type 12 ATV61W, the ATV660 replaces the E-Flex and M-Flex systems, and the ATV680 replaces the PowerGuard 18-pulse units.
That is a genuine VFD cross-reference, and still not a drop-in answer. The same document warns that ATV630 dimensions “can be significantly different than those of the same HP size ATV61” and that a retrofit into an MCC bucket “may impact the UL listing of the assembly.”
Cross-Brand Substitution: the Case Nobody Documents
No manufacturer publishes a validated equivalence between its own drive and a competitor’s. That is not evasion. Establishing one would mean comparing both units across output current at both duty classes, control method, feedback, communications, safety functions, dimensions, and listing status. Nobody tests a competitor’s product that thoroughly, and a claim made without that testing is a guess wearing a table’s clothing. No verified cross-brand VFD equivalent model exists.
Is Your Drive Actually Discontinued?
Many drives people believe are obsolete are still current, and the reverse is common: a unit running happily in a cabinet may have been out of production for years with its spares window closing.
This is why most obsolete VFD replacement projects start in the wrong place: the assumption comes from the age of the machine rather than the drive’s own record.
Reading a Model Number and a Nameplate Date Code
A VFD model number lookup starts with the drive’s label, not a search engine. The label carries the model family, power rating, voltage class, enclosure rating, and usually a serial number from which the manufacturing date can be decoded.
That date is the one most often skipped. Support life runs from manufacture, not from installation. A VFD retrofit planned around a four-year-old cabinet may be pulling a drive closer to twelve.
Where Lifecycle Status Is Published
Every major manufacturer publishes lifecycle information, though rarely where people look first:
- The lifecycle or phase-out portal, where milestone codes and dates are listed by order number
- The transition guide, published when a successor is designated
- Your distributor, who can query the manufacturer’s status against a full order code
End of Production, End of Spares, End of Repair: Three Different Dates
A discontinued drive passes through three separate thresholds, frequently years apart.
Siemens illustrates the pattern on the SINAMICS G180. The phase-out was announced with milestone P.M400 taking effect on 1 October 2024. Under P.M410, from 1 October 2026, the product is discontinued and only spare parts and service remain available. Final phase-out at P.M490 is dated 1 October 2035.
The practical reading: a drive discontinued in 2026 may still be supported into 2035. End of production is a planning trigger, not an emergency. End of spares is the date that forces a decision, because after it a single failed board can stop a line with no replacement path.
Compare the spares date against your maintenance horizon and your lead times. If the two are within a year of each other, the discontinued VFD replacement decision has already been made.
Using a Manufacturer’s Transition Guide
When a manufacturer designates a successor, the migration document is the most useful cross-reference artifact in existence. It is written by the only party with both drives on a test bench.
These guides list the replacement mapping by enclosure and rating, which parameters map across, changed terminal positions, discontinued options, and mechanical differences. What none contains is a guarantee that your application works, because the guide describes the drive and cannot describe your panel.
The specific trap is compatibility language. CMCO’s documentation states that all Series 4 option cards are compatible with Series 5 drives. It then records that using the S4IO card in a Series 5 drive invalidates the UL listing, because the S4IO card does not itself comply with UL, CSA, or CE standards. The card fits. It is compatible. It also voids the listing.
When the VFD Replacement Cross Reference Names the Wrong Drive
A named successor is a product recommendation, not a statement of equivalence. Four things routinely differ in ways the mapping does not convey.
Moved Terminals and Changed Control Wiring
Terminal positions move between generations, and a moved terminal can leave a functioning drive in local mode with the plant convinced the replacement is faulty.
The clearest documented case is the ABB ACS550 to ACS580 transition, where the analog input common moved from terminal X1-2 to X1-5. Wire the reference to the old position and the drive does not see a speed command. Nothing is broken. The reference is simply on a terminal the drive is not reading.
Safety inputs move too. Schneider records that the ATV61 used PWR and +24 terminals, whereas the ATV630 provides STO STOA and STOB, and that keypad and mounting kit part numbers change even though the cabling part numbers carry over.
Dropped Features: Feedback, Braking, and DC Bus
Some successors are genuinely narrower than the drives they replace, and the loss is a capability rather than a wire position.
Braking and DC bus. Schneider’s FAQ states plainly that the ATV600 “does not have provisions for connecting a Dynamic Braking Resistor or for using a DC Bus connection.” A site with a braking resistor fitted for a high-inertia stop cannot move to an ATV630 and bring that resistor with it.
Encoder feedback. The ABB ACS580 does not accept encoder feedback modules, so a closed-loop application on that platform has to move to the ACS880 instead. For closed-loop vector control, that is not a compromise to weigh. It is a gate.
A Successor That Does Not Cover Your Power Range
A transition guide can name a successor for a product family while covering only part of that family’s range.
Siemens is retiring the SINAMICS G180 and the SINAMICS G220 is its designated successor. The G180 spans a wider power range than the G220, and at least one repair-industry analysis notes that some facilities keep G180 units precisely for that reason. If your rating sits above the successor’s range, the path is not a swap at all. It is a redesign, or a repair-and-spares strategy until one exists.
A Retrofit That Invalidates a Listing
A physically successful retrofit is not the same as a compliant one, and the two are easy to conflate when the drive runs.
Schneider warns that retrofitting an ATV630 into an E-Flex, M-Flex, or MCC bucket “may impact the UL listing of the assembly.” CMCO’s case is starker: fitting a compatible option card voids the listing outright. If the panel carries a listing your insurance, your customer, or your local inspector relies on, verify the listing status after the swap, not just the run.
The Six Checks a Cross-Reference Table Does Not Run
Run these in order. The first can stop a replacement VFD drive selection on its own, and each of the rest can stop the installation.
1. Output Current at the Right Duty Class
This check replaces nameplate kW, and it is the one most often skipped.
Schneider’s ATV61 FAQ describes the replacement family as “set up for Normal Duty which indicates they are rated for 110% overcurrent capacity for 60 seconds,” then states that “when programmed for Heavy Duty the HP rating and current rating are decreased,” after which “the drive is then able to provide 150% of the new rating for 60 seconds.”
Read that again. Heavy Duty does not add capability to a fixed rating. It reassigns the same hardware, lowering the continuous rating to reserve thermal headroom for a larger overload pulse.
| Criteria | Normal Duty (ND) | Heavy Duty (HD) |
|---|---|---|
| Overload current | Around 110% for 60 s | Around 150% for 60 s |
| Continuous current, same frame | Higher | Lower |
| Torque profile | Variable torque, falls with the square of speed | Constant torque, shock loaded |
| Typical loads | Centrifugal pumps, fans, blowers | Conveyors, cranes, mixers, positive-displacement pumps |
Datasheets follow this shape: a frame listed at 92 A continuous in Normal Duty with 110% for 60 s reaches about 101 A, while the same frame in Heavy Duty lists at 88 A but reaches about 132 A for 60 s. The figures vary by frame size. The direction does not.
The check is a comparison, not a calculation.
I(rated, new, at matching duty class) >= I(FLA, motor)Compare the replacement’s continuous output current, read from the column matching your load, against the motor’s nameplate full-load current. Do not apply the motor’s service factor. Read the current column, not the kW row.
Goran builds panels for an integrator in northern Serbia and replaced a tripped 22 kW drive from stock in early 2025. Same kW, same voltage, and it ran the conveyor empty without complaint. Three weeks later the conveyor jammed and the replacement tripped on overcurrent within a second. The original had been a heavy-duty rated frame; the spare was normal-duty. The correct replacement cost more than the one he fitted, and the difference sat in a datasheet column he had not opened.
For the sizing method itself, how to choose a VFD covers it in full and VFD selection by load type covers how the load class is determined. This article only verifies that a candidate you have already chosen passes.
2. Control Method
Confirm the replacement supports the control mode the application actually uses. Sensorless vector on a conveyor and simple V/f on a fan are not interchangeable at identical ratings, because low-speed torque depends on the mode. Check the mode the old drive was configured for, not the best mode the new one offers.
3. Feedback and Encoder
If the old drive closed the loop with an encoder, this check is binary and it comes first. Confirm the replacement accepts the encoder type and resolution you have, and that it has the input card the application needs. This is where the ABB ACS580 and ACS880 split, and the check is most likely to send a project back to specification.
4. Communications and PLC Register Mapping
A drive that speaks the same protocol is not the same as a drive the PLC already understands.
Schneider’s documentation records that moving an ATV61 to an ATV630 on PROFIBUS requires PLC reconfiguration, because the device description file changes and the variables have to be remapped. The drive talks to the network. The program does not talk to the drive until someone updates it.
Budget for this. It is engineering time, it usually needs a controls engineer rather than an electrician, and it is most often discovered at commissioning.
5. Safety Functions and Listing Validity
Confirm the replacement provides the safety functions the installation relies on, that the wiring matches what the safety circuit expects, and that the machine’s compliance documentation still describes what is installed.
Two questions decide this. Does the replacement support the same stop categories and monitoring as the original provided? Does the retrofit preserve any listing the panel or the machine holds? If either answer is uncertain, it belongs with your safety and compliance contact, not on the electrical drawing.
6. Mechanical Fit
Heat, weight, and hole spacing decide this, and the enclosure dimensions in a datasheet will not settle it.
Check the footprint against the mounting plate rather than the cabinet, because a drive that fits the space may not fit the studs. Check the weight against what the structure and the installer can carry. Check the clearance the manual specifies above and below the unit, because the replacement may run hotter than the original. A replacement specified for a different IP or NEMA rating also changes what the cabinet has to do.
What to Record Before the Old Drive Comes Off the Panel
The cheapest hour of a VFD retrofit is the one spent documenting the old installation while it is still running.
Parameters and Embedded Logic
Capture the full parameter set before removal, from the drive itself rather than from a file you believe is current. VFD parameter backup covers the methods, and it is worth reading before the outage rather than during it.
Two things to watch. Firmware version matters, because a parameter set from a different revision may not restore cleanly. And where a manufacturer supports embedded custom logic inside the drive, a plain parameter copy will not transfer it. Yaskawa’s DriveWorksEZ is the commonly cited example, and parameter A1-07 indicates whether that logic is present.
Photographs, Wire Numbers, and Terminal Records
Photograph the drive in place, the terminal strip with every wire landed, the nameplate, and any adjacent equipment. Photographs cost nothing and answer questions weeks later that memory cannot.
Record the control signals by function and terminal, taken from the PLC I/O list rather than inferred from the wires. Note the motor nameplate full-load current, the figure the sizing check uses.
Dimensions, Hole Pitch, and Weight
Record the mounting hole spacing, not just the overall enclosure size, and the weight of what comes out and what goes in. A replacement with a different hole pitch means drilling a live panel.
Safe Isolation Before You Touch Anything
Verify no voltage at the incoming supply terminals, then on the DC bus, and confirm the bus capacitors have discharged. Capacitor discharge is not instantaneous, and the bus holds a dangerous voltage after the supply is removed.
Use a meter rated for the installation’s measurement category, and verify it on a known live source before trusting a zero reading. Where the site works to NFPA 70E or an equivalent standard, follow the site’s own procedure and arc-flash boundaries.
Marta maintains drives at a packaging plant in northern Poland and learned this the slow way. A drive failed on a Friday in 2024 and the replacement, ordered on kW, sat on the floor for two days because nobody could confirm which terminal the run command came from without tracing wires live. The next swap she documented first: cabinet photographed, every terminal recorded against the PLC I/O list, parameters captured, hole spacing measured. That drive went in on a single shift, and her note was that the two days had cost less than the two hours.
Deciding Whether to Replace at All
Replacement is not always the answer, and this article does not decide between repair and replacement. That decision, and the component wear intervals that inform it, belong to VFD troubleshooting and common VFD faults, which both carry a repair-versus-replacement framework. Component life cycles belong to VFD preventive maintenance, and cost context to the VFD price guide.
Spare Rotation: the Option Nobody Plans For
For a drive on a critical line, the strongest pattern is not a better decision at failure. It is not being forced to make one.
Install the new or spare drive immediately to restore production, then send the failed unit for repair and return it to stores as the next spare. The line comes back at once, the failed drive becomes an asset rather than a disposal, and the plant ends up with a rotation instead of a single point of failure.
Ravi runs engineering at a steel processing plant in Gujarat that had one 75 kW drive with no spare on a line that could not stop. When it failed in 2023 the replacement took nine days to arrive and the line was down for all of them. He now keeps a spare on the shelf, rotates it in on the next planned outage, and repairs the replaced unit into stores. The second time that line failed the changeover took four hours.
The precondition is knowing the risk before it materialises. A drive whose spares window closes in eight months is a spare-rotation candidate today. Whether a failed drive is repairable stays with the troubleshooting guides; once replacement is the direction, the cross-reference and the six checks decide which drive.
The Second-Hand and Grey-Market Trap
A failed or discontinued drive creates urgency, and urgency is what the second-hand market sells into.
Stored drives need reforming. A drive that has sat unpowered for a long period needs its DC bus capacitors reformed before being energized and loaded. This is discussed in field forums rather than in most published guidance, and it is worth taking seriously: skipping it is reported to damage the capacitors, and a capacitor that fails under bus voltage can rupture.
Counterfeits are a global supply-chain problem. ABB publishes guidance on counterfeit spare parts and a verification method, and Mitsubishi, Yaskawa, and Siemens have issued comparable warnings. ABB notes that the most commonly counterfeited component is the IGBT, but that fake fans, control boards, and entire drives have been seen. Serial numbers are usually the most reliable giveaway, and non-genuine parts generally void the warranty. Regulators in several regions have acted on this, with published cases involving used units relabelled as new and sold through ordinary channels. Buy through the manufacturer or an authorized distributor, and treat a price well below the market as a signal rather than an opportunity.
A refurbished drive is not automatically a bad one. A unit rebuilt by the original manufacturer, with a warranty and a documented parts history, can be a sound spare. The risk is units of unknown provenance sold as new, where neither is real.
Frequently Asked Questions
How do I find a replacement for a discontinued VFD?
Identify the model family, rating, and manufacturing date from the nameplate, then check the manufacturer’s lifecycle portal for discontinuation status and the spares and repair end dates. If a successor is designated, read its transition guide, then run the six checks before ordering.
Can I replace a VFD with a different brand?
Yes, and it is common, but no validated cross-brand equivalence table exists. Treat a cross-brand swap as a new specification rather than a substitution, with particular attention to output current at the correct duty class, feedback, and communications.
Will a different VFD model fit my cabinet?
Not necessarily, even at the same rating. Check the mounting hole spacing rather than the overall dimensions, the weight against your mounting structure, the airflow clearance the manual specifies, and the enclosure rating.
Do I need to reprogram a VFD after replacement?
Assume yes, even when the new drive accepts a restored parameter set. Firmware differences can prevent a clean restore, embedded custom logic may not transfer with a parameter copy, and a communications change also requires a PLC program update.
What should I record before removing a VFD?
The full parameter set and firmware version, the motor nameplate full-load current, the control signals by function and terminal taken from the PLC I/O list, photographs of the drive and terminals in place, the mounting hole spacing, and the weight of both units.
Is my VFD obsolete?
Not necessarily. Support life runs from the manufacturing date on the nameplate, not the installation date. Check the lifecycle portal by order code, and identify the end of production, spares, and repair dates separately.
How do I read a VFD model number?
A model number typically encodes the product family, power rating, voltage class, and enclosure rating, with the structure set by each manufacturer. Read it from the nameplate rather than a purchase record, and note the serial number separately, since the manufacturing date is usually encoded there.
Are refurbished VFDs safe to buy?
It depends on who refurbished them. A unit rebuilt by the original manufacturer or an authorized service partner, with a warranty and a documented parts history, can be a reasonable spare. A unit of unknown provenance sold as new carries neither.
Conclusion
A VFD replacement cross-reference answers one question well: which model succeeded which. Everything that decides whether the swap works sits outside its scope.
Six checks close that gap. Confirm output current at the duty class matching your load rather than the nameplate kW. Confirm the control method. Treat encoder feedback as a gate. Map the communications and budget for the PLC work. Verify the safety functions and the listing. Measure the mounting hole spacing, not the cabinet.
Then record what you have before anything comes off the panel, and read the lifecycle dates as three separate thresholds rather than one.
Choosing a Replacement Drive
Send us the nameplate photograph, the drive model and order code, and the motor full-load current. Our engineers will confirm the rating against the correct duty class, flag any feedback or communications constraint, and come back with a replacement and the parameters that need to change. Talk to our engineers before you order, not after the drive is on the floor.
