What is the difference between a stepper motor and a servo motor, and which has a larger permissible inertia?

Of course! Gain adjustment is an adjustment for optimal control according to the load.

That's right. The responsiveness and stability of servo motors are strongly affected by the magnitude and variation of the load inertia and the mechanical rigidity of the device itself. If a servo motor is used in a device with low mechanical rigidity, such as a belt/pulley mechanism or a device with a large load inertia, it may oscillate and fail to operate, so gain adjustment is necessary.

It seems kind of difficult…

It might seem difficult when you consider having to adjust to the mechanism. However, recent servo motors are equipped with an automatic tuning function, so in some cases, adjustments can be made in a relatively short period of time.

Really?

I think it would be difficult to adjust gain for an elevator with variable load mass, or a mechanism with load fluctuation like a crank mechanism or cam mechanism. The advantage of stepper motors is that they can achieve high responsiveness without the need of gain adjustment, regardless of the mechanism, so I think it's a good idea to suggest them according to the customer's mechanism.

So that's what you mean! Conversely, if there is no load fluctuation, does that mean we should choose a servo motor?

Not necessarily. Vex, do you know which is more advantageous for a load with a large load inertia, a stepper motor or a servo motor?

…。

Actually, stepper motors are more advantageous. If a servo motor exceeds the recommended load inertia (permissible inertia), it exceeds the automatic tuning adjustment range, resulting in unstable operation. As a result, problems such as "inability to be agile in following commands" and "hunting at stop" occur.

On the other hand, for the αSTEP, compared to the same size servo motors, rotor inertia and permissible inertia is larger, so it can operate stably even under conditions where the load inertia is large.

So stepper motors have large permissible inertia!

That's right. There was an actual case in the past where a customer who was using 750 W servo motor asked for replacement consultation, and after confirming the operation pattern and application, it was found that the motor could be driven by 400 W-class AZM69. At that time, the index table didn't require speed, but if you have a proper conversation with the customer, I'm sure you can make more beneficial offer.

Some customers don't understand the difference between stepper motors and servo motors and select servo motors, but I learned that we can propose more suitable products if we have clear understanding of the customer's mechanism and usage. We will continue to introduce easy-to-use products while considering what is best for the customers!

I hope you can make optimal proposals, making use of motor sizing tool. I'm rooting for you!

I'll do my best!