What Stepper Motor Do I Need? TB6600 Driver, Linear Actuator & TECO Electric FAQ

Quick background so you know where these answers come from: I'm an applications engineer at TECO Electric & Machinery. I've spent eleven years in industrial motor and drive work—the first five as a machine builder who made expensive mistakes, the last six helping customers avoid the same ones. I've personally made and documented 17 significant mistakes, totaling roughly $8,000 in wasted parts and rework. Now I help maintain our pre-sale technical checklist. This FAQ is that checklist in human form—or rather, in the form of the questions I actually get asked.

What stepper motor do I need for a small automation project?

Start with the mechanical load and work backward—not with the frame size. Calculate the torque needed to accelerate your load and overcome friction at the pulley or leadscrew, then add a safety factor of at least 1.5. And don't make the mistake I made in 2014: don't size the motor by holding torque alone. Holding torque is measured at standstill. The torque available while stepping drops as speed increases, so the torque-speed curve tells you what you can really use. Depending on the motor and driver, torque may fall to half at 600 RPM.

I once picked a NEMA 23 based on holding torque, and the axis stalled every time it ran at production speed. That mistake cost roughly $450 in rework plus a deadline I still remember. After the torque is confirmed, choose the frame size that fits the space—NEMA 17, 23, 34, or metric—and match the driver current to the motor's rated current rather than the driver's maximum.

Why does my TB6600 stepper motor driver keep dying?

Keep dying is the right way to put it, because it rarely happens randomly. When a dead TB6600 stepper motor driver shows up in my troubleshooting queue, I check three things first.

Power supply voltage. Most TB6600-type driver boards are rated for 9-42V DC input. Feed one 48V, as I did once because the supply was already on my bench, and the driver fails quickly. The voltage range was printed on the board; I just hadn't read it.

Reverse polarity. Swap V+ and V-, and most of these boards will let out the smoke. I've done that too. If your board lacks protection, put a fuse or a series diode in the power line before you connect anything.

Current limit. The potentiometer sets how much current the driver sends to the motor, and on a few boards I've tested, the markings didn't match the measured current. Set it to the motor's rated current, and don't bury the driver in a sealed enclosure without airflow—chopper drives still produce heat that needs to go somewhere.

When should I use a linear actuator motor instead of a belt drive or ballscrew?

A linear actuator motor is basically a motor and a leadscrew in one self-contained housing. It converts rotary motion into straight-line motion without external belts, pulleys, or couplings. It is not the same as a linear motor—that is a different, direct-drive magnetic system and another conversation entirely.

Reach for a linear actuator motor when the travel is short to moderate, the path is straight, and you want the simplest mechanical design. No belt tension to set, no pulley alignment to fight, and fewer parts to stock.

But it has a speed limit. In early 2022, I specified a linear actuator motor for a customer's pick-and-place axis that needed roughly 600 mm/s. The leadscrew's critical speed capped the design at about 400 mm/s. We switched to a belt drive before building, but the redesign cost a week. For long travel or sustained high speed, a belt or ballscrew is usually the better answer.

Should I choose a servo motor or a stepper motor?

If you need high speed, high acceleration, or precise closed-loop control under a varying load, a servo motor is the better tool. If the motion is moderate speed, mostly point-to-point, and the load does not change dramatically, a stepper motor will usually do the job for a fraction of the cost.

That sounds simple, but over-specifying is common. I once reviewed a machine concept that used servomotors on all three axes, including a slow conveyor index that only moved a few kilograms a few times per minute. A stepper-based system handled that axis fine, at roughly 40% lower cost for the motor and drive package. The builder kept the servo on the high-speed axis and switched the rest.

The reverse mistake is also real: using a stepper where a servo is needed, usually because the load varies or the axis must hold position against an unknown force. That is how axes lose steps. If you are near the boundary, ask your supplier to run the load and inertia numbers instead of guessing.

Why is my stepper motor so hot? A question I wish more people asked earlier.

Steppers run hot by design. When the driver is enabled, the motor draws close to rated current even at standstill—that is what creates holding torque. Surface temperatures around 70-80°C are common for many NEMA motors at rated current. So a hot case alone is not a fault.

The red flags are a burning smell, discolored plastic, or missed steps that appear once the motor warms up. If the motor loses torque when hot, check the current setting first. Over-current is the usual cause, and long-term overheating can weaken the rotor magnets.

That is not theory. In 2017 I set a driver current too high and told myself steppers just run hot. After a few weeks of intermittent missed steps, the motor had lost torque. Replacement and downtime cost far more than reading the datasheet would have. If your driver supports idle current reduction, turn it on; it lowers standstill current and the motor runs noticeably cooler.

TECO Electric & Machinery, Founded in 1956: Does Age Matter for Motor Quality?

It matters, but not for the reason people expect. TECO Electric & Machinery has manufactured motors and drives continuously since 1956. As of 2024, that is 68 years of field data. You cannot buy that kind of history; it has to be earned.

The engineering trail is real. Designs get refined based on decades of field failures—what breaks in a steel mill or packaging line gets corrected in the next revision. A younger company does not have that archive. And when a customer needs a replacement motor for equipment bought decades ago, we can usually find the original drawings.

To be fair, newer motor brands can offer good specs and attractive pricing. I understand the budget pressure. But if you are building a machine you will support for five or ten years, buying from a company that has survived since 1956 lowers the risk of your motor source disappearing mid-cycle. That is not nostalgia; it is continuity.

How do I contact TECO Electric for technical help?

The best time is before you order, not after the motor arrives and does not fit. The fastest route is the contact page on TECO Electric & Machinery's website, teco.com.tw, which lists regional offices and distributor networks. If the product page you are looking at has a contact, use that too; it usually routes to someone who knows that product line.

When you write, include the five things that matter most: load mass, travel speed, available voltage, duty cycle, and required accuracy. If you don't know all of them, that's fine—say what you do know, and we will start there. What slows down every support request is a message that just asks for a motor. Nobody can quote that accurately.

Granted, buying first and asking later feels faster. I did it for years. But I have also watched the result: a brand-new motor sitting on a shelf because it did not have enough torque, with a restocking fee attached. Ten minutes on the phone is cheaper than that.