If your name is on the PO for a motor, stop browsing the catalog before you read this. The maxon-motor lineup is pretty broad—brushless DC motors, gearmotors, servo systems, and even e-bike drive units. This checklist is for the buyer or engineer who needs to narrow that lineup in the next two weeks—and keep the total cost under control. Six steps, no theory. I’ve managed procurement budgets for small automation projects since 2019, and this is the order I actually use.

The vendor failure in Q2 2023 changed how I think about motor procurement: one wrong winding voltage on a $3,000 order, and suddenly the “premium” motor didn’t seem overpriced. Now I start every motor purchase with this checklist.

Step 1: Define the Duty Cycle Before You Look at the Price

If you don’t have a duty cycle, every quote is a guess. Maxon publishes torque-speed curves in every official datasheet, but those curves only tell the truth when you know your load, speed range, and how many minutes the motor actually runs. More than one PO I audited failed because the buyer skipped this step. What I mean is: the continuous torque rating is the number that drives the price, not the peak torque.

For the maxon ebike motor in our prototype, the duty cycle is brutal. It runs in bursts, but the thermal mass still has to handle repeated starts. Calculate the RMS torque. If you don’t want to do the math by hand, at least download the motor datasheet PDF and use the performance curves before requesting a quote.

Step 2: Compare TCO, Not the Sticker Price

The maxon motor price is rarely the whole story. I manage the budget for a 12-person robotics company, and I track every invoice in a cost system—about $180,000 in cumulative motor and drive spending since 2019. In my opinion, the real cost difference between a maxon motor and a lower-priced alternative comes from installation, commissioning, and rework, not the initial quote.

Total cost of ownership formula I use: purchase price + shipping + integration + spare parts + downtime risk + rework. I once chose a slightly cheaper motor and paid more for a shaft modification and an adapter plate than the maxon quote would have cost. So glad I started tracking line-item costs; otherwise I’d never have seen the pattern.

“Cheap” is just the first line of the TCO sheet. The question is where the sheet ends.

Step 3: Answer “What’s a VFD?” Before Your Spec Goes Sideways

“What’s a VFD?” is usually an engineer’s question, not a buyer’s, but I’ve sat in enough kickoff meetings to know it becomes a procurement problem. A VFD—variable frequency drive—controls the speed of a standard AC induction motor by varying the frequency and voltage of the power feeding it. If your plant already uses induction motors for pumps or conveyors, a VFD is the thing that gives you speed control. If you’re spec’ing a maxon brushless DC motor instead, you don’t need a VFD; you need a compatible servo controller.

This is the step where budgets get blown. The motor and the drive have to match. When I explain the difference to our team, I literally draw the induction motor diagram—stator, rotor bars, windings—next to a BLDC schematic. The induction motor diagram shows a motor that gets its torque from a rotating magnetic field. A brushless DC motor has permanent magnets on the rotor and electronically commutated windings. Different machine, different controller, different spare parts.

Step 4: Spec the Servo Motor Gearbox at the Same Time as the Motor

A servo motor gearbox is not an afterthought. It changes the output torque, but it also changes the reflected inertia, backlash, and overall efficiency. If you pick the gearbox after the motor, you’ll often end up with a motor that’s oversized—and oversized motors cost more in every category.

Maxon’s planetary gearboxes are matched to specific motor models. Use their online configurator rather than trying to mix and match. At least, that’s been my experience with small-format servo systems. The same thinking applies to a maxon ebike motor: the gearbox and the controller are usually part of one system, and mixing components from different product families gets expensive fast. The gearbox and the motor are rarely on separate POs if the engineer and buyer talk before ordering.

Step 5: Verify the Datasheet, Not the Marketing Blurb

maxon motors are a premium brand, but premium brands can still be specified wrong. Download the official maxon-motor datasheet for the exact part number on the quote. Check rated voltage, no-load speed, and continuous current. If the datasheet doesn’t answer a question, ask for the factory test report. For AC induction motors, I also check NEMA MG 1 or IEC 60034 ratings if a VFD is involved—but for a maxon motor, the official spec sheet is what you’ll be held to.

Don’t assume “Swiss Made” means “automatically fits this application.” It doesn’t.

Step 6: Add an Acceptance Test to the Purchase Order

This is the step I skipped in my first year, and it cost me a classic rookie mistake: I approved a PO with no test plan. Learned that lesson when a batch of motors arrived and 10% of them were outside the speed tolerance. The rework cost almost as much as the original order.

Before you send the PO, write down what “good” looks like. No-load speed? Temperature rise after 30 minutes? Noise level? If you don’t have acceptance criteria, return shipping is a line item you’ll discover later. If I remember correctly, our current policy requires at least a no-load current test before we sign off. If you ask me, the acceptance test is the most overlooked line in the budget. The best part of finally building this into every order: no more midnight panic about whether the motor will work when it arrives.

Last-Minute Cost Traps

  • Accessories can exceed the motor price. Connectors, cables, filters, and gearbox output flanges should go on the same PO as the motor to avoid separate shipping charges.
  • Lead time quotes change weekly. Ask for a written delivery date before you approve the budget.
  • If you’re using a VFD with an induction motor, don’t buy the motor and the VFD in separate orders. Matching the voltage and frequency rating is cheaper when it’s one purchase order.
  • If your project is a servo axis, don’t finalize the motor until the servo motor gearbox ratio is in the drawing.
  • If you’re looking at a maxon ebike motor, verify the controller and wheel sensor compatibility before comparing the maxon motor price with a cheaper hub motor.

There’s something satisfying about a motor installation that starts up on the first try. It doesn’t happen by luck; it happens when the duty cycle, controller, gearbox, and acceptance test are all locked in before the PO goes out. That’s the only way I buy motion components now.