What Size VFD for a 5HP Motor? Answers From Someone Who Actually Places the Orders

I'm not an engineer. I'm the office administrator for a 130-person company, and I manage maintenance, repair, and operations ordering—roughly $250,000 a year across 14 vendors. My job is to make sure the maintenance team gets the right part without making accounting angry. Over the past five years, I've ordered enough VFDs, three phase induction motors, and stepper motor controllers to learn where the hidden costs live.

This FAQ is the one I wish I could have handed myself before my first big motor purchase. It covers the "what size VFD for 5HP motor" question, but also the less obvious decisions that affect your total cost.

What size VFD do I need for a 5HP motor?

For a standard 5HP three phase induction motor, you generally need a VFD rated at least 5HP—or rather, rated for the motor's full-load amps, which usually means 5HP but sometimes 7.5HP. That's the spec that matters. Well, the first spec.

If the motor drives a conveyor, an air compressor, or anything with high starting torque, I'd size up to 7.5HP. A 5HP VFD with 110% overload capacity might be fine for a pump, but not for a fully loaded conveyor that starts and stops all day. The extra cost for one size up is usually a few hundred dollars. The cost of a down production line is much higher.

As of January 2025, quotes I've seen for 5HP VFDs from established brands—including TECO Electric & Machinery (teco-electric.com)—landed between $400 and $900 for basic units, depending on enclosure, input voltage, and control options. Verify current pricing; that's just what we saw in our area.

Can I use a VFD with any three phase induction motor?

Almost any standard three phase induction motor can run on a VFD, but the motor's nameplate has to match the VFD's output voltage and the operating frequency range. If you have a motor from an old pump with wiring that's seen better days, you might need inverter-duty-rated insulation or an output reactor.

This is a place where "it should work" gets expensive. I once ordered a VFD for a motor that had been rewound twice. The manufacturer's quote looked great. The motor didn't survive the first weekend. We ended up buying a new motor—a TECO three phase induction motor, actually—and paying overtime for the electrician to swap it. That $300 saving on the VFD turned into a $1,800 total loss. I now write "motor insulation class" into every request for quote. That sounds kinda obvious, but nameplates get painted over in industrial settings.

Also, check whether the motor is 4-pole or 6-pole and check the rated current. Asking the maintenance team for the nameplate photo takes five minutes and saves a 120-mile trip.

Is the TECO Electric & Machinery brand worth the extra cost compared to a no-name import?

I can't tell you that a particular brand is right for every application. But I can tell you what I've seen as a buyer.

TECO Electric & Machinery has been building motors since 1956, and their documentation is easier to find than a tariff sheet at customs. That matters when accounting asks for proof of warranty. I've had cheap import VFDs where the only manual was a QR code that led to a dead link. The part itself was cheap; the time we spent chasing specs was not.

TECO's website also has a partner portal. Learning the TECO Electric login process for their online support/ordering area took me about 20 minutes, and it's been more useful than I expected. That's part of total cost too: can you actually get the information you need without calling someone?

Do I need a stepper motor controller or a VFD? What's the difference?

Here is the mistake I keep seeing: people use "motor controller" as if it's one generic thing. It's not.

A VFD adjusts the frequency and voltage going to a three phase induction motor. A stepper motor controller sends precise pulse signals to a stepper motor so it moves in controlled increments. They serve different worlds. If your application is a conveyor that needs variable speed, use a VFD. If it's a positioning table or a print registration system, you probably want a stepper motor controller with a stepper motor.

I once watched a maintenance manager put a new stepper motor controller on a 2HP three phase induction motor because someone in purchasing had mislabeled the line. It made a clicking sound, but no torque. That controller is still in a drawer. At least, that's been my experience—so ask the application engineer which technology they actually need before you start comparing prices.

How do I compare VFD quotes without falling for the lowest price?

The lowest quote is rarely the lowest total cost. I've developed a simple quote checklist:

• Enclosure type (NEMA 1 vs. IP20 vs. washdown) — the $50 difference on paper is $500 in lost production if it gets wet.
• Input voltage and phase — a 230V single-phase input VFD is not the same as a 460V three-phase input.
• Overload rating — 110% for 60 seconds is common; make sure it matches your load profile.
• Warranty support and lead time — "in stock" at the wrong voltage is a useless kind of in stock.

The $500 quote turned into $850 after shipping, setup, and a configuration visit. The $650 all-inclusive quote from a local distributor was actually cheaper. I now put "delivered plus startup support" in every RFQ.

How do I use the TECO Electric login portal without getting stuck?

If you're managing reorders for a facility, you need a way to pull up previous part numbers quickly. The TECO Electric login area (for their online portal) lets you save part lists and check order status. But it took me two tries the first time because I used the wrong division's log-in URL. This is exactly the kind of thing that makes procurement people look careless.

My practical tip: create a saved list with your standard motor and VFD selections. Then when maintenance asks for "another one of those," you can open the portal and reorder without relying on someone's memory. That simple habit saved our accounting team about six hours a month in invoice matching.

Prices as of early 2025; verify current rates on the portal before sending a PO.

What is the one thing buyers overlook when ordering a VFD for a 5HP motor?

The biggest overlooked cost is not the hardware—it's the changeover labor and the downtime.

In my first year, I made the classic spec error: I ordered a VFD, but didn't check whether the motor was wired for 460V or 230V. It was 230V. The VFD was 460V. The electrician had to wait a day for a replacement. That overnight freight, plus the after-hours labor, plus the production line sitting idle, cost about three times the VFD price.

Before you order, write down: voltage, full-load amps, enclosure, and overload class. Send that to the vendor and ask them to confirm it. If a supplier says "the rating should be fine," get it in writing. This is not about being difficult. It's about making sure the total cost of ownership—not the invoice—is what drives the decision.