Motor Test Bench Specification Checklist (Free Template)

Introduction

Most failed bench projects do not fail on the hardware. They fail on a spec written too late or too loose, and the gap shows up only after the purchase. A bench rated for 10 Nm peak cannot validate a motor that needs 12 Nm continuous, and no firmware update fixes that.

A good test bench specification turns vague wishes into numbers a vendor can quote and build. This article gives you a structured checklist you can copy. Fill each field with your own values, send it to a vendor, and you remove most of the guesswork from the project.

Takeaway: the spec, not the hardware, is where most bench projects are won or lost.

The Specification Checklist

Work through the six groups below in order. Each one has a small table: the parameter to define, what to specify, and an example value you can replace with your own. Start from the motor you test, because it sizes everything downstream.

Motor Under Test

Everything begins with the motor. Write down every motor you plan to test today, plus what is on your roadmap for the next two years. Size the bench to the largest of them, not the average.

As a rule, add about 20% headroom on torque and speed over your largest motor. A frame that fits only today’s smallest motor will block your roadmap later.

Load and Dyno Requirements

The dynamometer, or dyno, is the load that the motor works against. Its type decides which tests you can run. An active dyno can both absorb and drive the motor, which you need for regeneration and four-quadrant work. A brake can only absorb.

If you are unsure which dyno fits, decide the tests first, then pick the load that covers them. A wrong dyno type is hard to fix after install.

Measurement and Accuracy

Your results are only as good as your sensors. Specify the range and accuracy of each one against your smallest signal, not just your largest. A torque sensor sized for 50 Nm measures a 0.5 Nm point poorly.

Check the torque accuracy at the lowest torque you care about. For why this matters, see our guide to the torquemeter in test benches.

Takeaway: specify accuracy at your smallest value, where cheap sensors fail.

Control, Protocols and Data

This is where many benches disappoint. You want automated sequences, live logging, and clean export, not just a live dial you have to watch. Define the interface the bench must speak so it fits your lab.

Ask one concrete question of any vendor: can the software run an unattended endurance test overnight and log every channel. If not, you pay for it later in engineer hours.

Safety and Environment

A spinning motor stores real energy, so safety is a requirement, not an option. Specify the fail-safe behavior you expect, and the room the bench has to live in.

A good bench fails safe. If a sensor drops out or a limit is crossed, the system stops the motor on its own. See how this works in emergency systems on a motor test bench.

Mechanical and Footprint

The last group covers the physical fit. It rarely decides the project, but a bench that does not fit your bench top or your power supply is a slow, expensive surprise.

Treat portability as a tie-breaker. It matters only when several teams share one bench or you demo away from the lab.

How to Use This Checklist with a Vendor

Fill in the example column with your own numbers, then send the whole table set to each vendor before you ask for a price. Three habits make this work better.

First, share peak and continuous values, not one number. A vendor sizes the frame on continuous and the dyno on peak, so a single figure hides risk. Second, mark which fields are hard requirements and which are nice to have. That lets a vendor offer a sensible build instead of guessing. Third, ask the vendor to quote against your spec, line by line. If a field cannot be met, you want to know before the purchase order, not after delivery.

Takeaway: a quote that answers your spec line by line is worth more than a lower price that ignores it.

Download the Template

The table set above is the full checklist. Copy it into your own document, or grab the formatted template to fill in with your team. Keep one copy per motor family. When a new motor lands on your roadmap, you update a few fields instead of starting the spec from scratch.

Pros, Cons & Trade-offs

A written spec costs time up front. That time is small next to the cost of a bench that almost fits.

No spec is perfect on the first pass. The common mistake is skipping the continuous ratings and the accuracy at low values, then discovering the gap during the first real test. Spend the hour up front.

How SOLO Helps You Turn the Spec into a Bench

At SOLO we read a spec like the one above and build the bench around it, rather than fitting your motors into a fixed envelope. We customize the dyno, the sensors, the protocols, and the report to your needs at any level. The benches support DC, BLDC, PMSM, and AC induction motors, with active or brake loading, torque and temperature sensing, and automated logging over CANopen or EtherCAT. If a field in your checklist sits outside a standard catalog bench, that is usually where a customizable build pays off. You can see the current SOLO motor test bench and send us your filled-in spec.

Conclusion

A motor test bench specification is just six groups of numbers: the motor under test, the load and dyno, the measurement and accuracy, the control and data, the safety and environment, and the mechanical fit. Fill each field with your own values, share peak and continuous figures, and check accuracy at your smallest signal. Then send the spec to a vendor and ask for a quote that answers it line by line. If you want a second opinion on your numbers, the SOLO test bench page is a good next step, and our team can review your checklist.

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