Earlier this month, I spoke with Viet Le, Senior Sales Engineer, Oriental Motor at the MD&M East/ATX East show in New York City. The company was showing off its AZ series of closed-loop absolute mechanical encoder stepper motors—they feature low vibration and high efficiency, and you don’t even have to purchase a battery back-up or external sensors.

“It can monitor position up to 1800° rotation,” Le said. “We have a couple different driver options as well. You can have DC input, or AC input.

According to Le, what’s unique about this particular package is the high holding torque at low speed.

“If you have an application where speed is not critical, where you don’t need 50,000 or 500 rpm, it would be a good package to have. When you do a direct comparison on the torque on this particular stepper package with a servomotor, you basically get more torque at the lower end. On a servo, you can achieve that particular torque, but you have to ramp it up,” he said. “And you can only operate in that region for a few seconds, and you have to drop it down again. Pricewise, it’s almost half the cost of a servomotor. So, that’s a huge benefit, especially when everybody’s looking for low cost and best production.”

Le said the encoder basically has a set of gears, and each of the gear teeth is magnetized with a north pole and south pole. Based on how it’s aligned, the angles of the gears align, kind of like a clock.

“The circuit actually detects the position and that how it detects where the encoder is. Let’s say when you run the motor, you have a power failure. You can plug it back in again, and it’s going to continue to move. You’re not going to have any issues, you don’t have to have a sensor to home it. Once you establish your home position, you never need to home your sensor again.

You give it one input, it’s going to go back to where we established it.”

The AZ is available with a built-in controller or pulse input driver that reduces heat generation from the motor through the use of high-efficiency technology. Features include:

• Battery-free, mechanical absolute encoder
• Closed-loop performance, no hunting or gain tuning
• AC or DC input types
• Wide range of gear types for inertia matching and higher torque

Le said that linear and rotary actuators will be coming soon and that an electromagnetic brake type is also available.