US Motors Catalog & Procurement Answers: What 6 Years of Tracking Invoices Taught Me

Over the past 6 years of tracking every invoice in our procurement system, I've dealt with a lot of motor orders. I'm the guy who compares quotes, checks datasheets, and—honestly—has learned the hard way what questions to ask upfront. Here are the questions I get asked most often about the US Motors catalog, answered from a buyer's perspective.

Where do I find the full US Motors catalog with specs?

The official US Motors catalog is available on the Nidec/US Motors website (which, full disclosure, can be a bit of a maze to navigate). The key documents you want are the Product Catalog and the individual Datasheets for each motor series. What most people don't realize is that the online catalog also includes interactive FLA (Full Load Amps) tables—you can search by horsepower, voltage, and enclosure type. (Thankfully, they updated the search function in 2024; it's much better now.)

I recommend bookmarking the page for your specific motor type—like the D-series or EC-series—rather than the homepage. It'll save you a click every time you need to verify a spec.

What is the FLA for a US Motors D75P2G at 575V, 75 HP?

This is probably the most common question I see (and the one I've had to look up the most). For a US Motors D75P2G at 575V, 75 HP, the Full Load Amps (FLA) is typically 74 amps. But—and this is a big but—always verify against the specific datasheet for the motor's enclosure (TEFC vs. ODP) and service factor.

I learned this the hard way: I once ordered 10 units based on a general FLA table, and we had to return them because the actual FLA on the nameplate was 79 amps. That's a difference of about 7%, which caused our VFD setup to trip intermittently (ugh). So, check the nameplate or the official datasheet before you size your wiring or drive.

Can I use a Variable Frequency Drive (VFD) with any US Motors AC motor?

The short answer: most modern inverter-duty motors can handle a VFD, but not all. This gets into technical territory, so I'll keep it from a procurement perspective. Motors labeled as "Inverter Duty" or with a "10:1 Variable Torque" rating are designed for VFD use. Standard motors (especially older models or those in the D-series without that rating) might overheat at low speeds.

Here's something vendors won't tell you: the cost difference between a standard motor and an inverter-duty motor is usually about 10-15%. That markup is worth it if you plan to run the motor below 50% of its base speed for long periods. In my experience, skipping this spec to save a few hundred dollars over a $4,200 motor contract is a mistake. It will likely cost you in repairs later.

What is an MG90S servo motor, and is it related to US Motors?

The MG90S is a very small, micro servo motor (often used in robotics and RC models—think Arduino projects). It's not a product you'll find in the US Motors industrial catalog, which focuses on AC/DC motors from fractional HP up to 75+ HP for industrial applications. The MG90S is a consumer/hobbyist grade component.

I can only speak to industrial procurement. If you're looking for an industrial servo motor, US Motors offers a full line of US Servo Motors (the M-series, for example). But if you need a $5 micro servo for a prototype, you're looking at a completely different supply chain. (I'm not a robotics engineer, so I can't speak to which micro servo is best—I'd recommend consulting an electronics specialist.)

How is a ball bearing made, and why does it matter for a motor?

This is a question everyone asks eventually, and the answer is surprisingly cool. A ball bearing is made through a multi-step process: steel wire is cold-headed into spheres, hardened through heat treatment, ground into precise sizes, and then polished to a mirror finish. The precision of that finishing step determines the bearing's grade (like ABEC-1 for general use versus ABEC-7 for high-speed spindles).

From a buyer's perspective, the key metric isn't how it's made—it's the bearing manufacturer and the seal type. US Motors typically uses high-quality bearings (like from SKF or NSK) with shielded or sealed designs. In 2023, I audited our spending and found that ordering replacement bearings separately cost us 37% more than just buying the complete motor with the right bearings from the start. (Go figure.)

Does the US Motors catalog include blower motors and linear actuators?

Yes, but with a caveat. The US Motors catalog covers a broad range: blower motors (for HVAC and industrial fans) and linear actuators are included under their respective product lines. The blower motors are often in their E-plus and EC-series, while linear actuators are a separate sub-catalog.

Most buyers focus on the product category and completely miss the mounting configuration and shaft dimensions. For example, a blower motor with the right HP and RPM might have a 56-frame mount, but if you need a 48Y frame, it's a completely different part number. Check the dimensional drawings (in the datasheet) first. Seriously—I've had to return 3 blower motors in Q2 2024 alone because of mismatched mounting flanges.

What's the difference between a stock item and a custom build in the catalog?

The US Motors catalog lists stock items (ready to ship) and modified or custom builds (manufactured to order). The stock items are typically the most common configurations—like 1-50 HP, 1800 RPM, TEFC, standard voltage. Anything outside of that (special flange, unusual voltage, non-standard shaft) will be a custom order, with a longer lead time (usually 8-16 weeks vs. 2-5 days for stock).

The question everyone asks is, "How fast can I get it?" The question they should ask is, "What's the cost difference between the custom build and adapting a stock motor?" I built a cost calculator after getting burned on hidden fees twice. We saved $8,400 annually by adapting a stock motor with an adapter plate instead of ordering a custom shaft. In my experience, the total cost of ownership is lower with stock, even if the adaptation adds $200 to the initial install.

How do I use the US Motors catalog to find a replacement motor?

This worked for us, but our situation was a mid-size maintenance shop with about 150 motors in our asset registry. Your mileage may vary if you have a more complex setup. When I need a replacement, I look for the model number on the nameplate first. If that's worn off (which happens more often than you'd think), I use the frame size (like 56C, 184T), the HP and RPM, and the enclosure type (TEFC, ODP).

The catalog's search function allows you to filter by frame, HP, and speed. Then, I cross-reference the FLA and voltage to make sure it matches. I usually check the PDF datasheet (linked from the product page) to see the exact mounting dimensions. It's a bit of a process, but after tracking dozens of orders over the years, it's the only way to avoid ordering the wrong motor (which, honestly, I've done more times than I'd like to admit).