A simple way to choose a stepper drive is to look for four things — voltage, current, microstepping, and maximum step pulse rate. Ensure that the drive can handle a wide range of current so that you can test the system at different voltage levels to fit your application. The driver should output at least 1.4 times the motor’s rated current. Choose a driver that has several step resolutions to test different microstepping settings to get the smoothest motion. Finally, make sure the driver can receive enough step pulses to rotate your motor at the desired speed. Sometimes drivers are limited to something small like 10 kHz. If you’re hoping to microstep even at 8× with a 1.8° stepper, your maximum revolutions per sec speed is 10,000/(8 × 200) = 6.25 rps.

Microstepping can increase the resolution of a system, which smoothes rotation and prevents vibration and noise. However, problems will arise if incorrect voltage is applied to a PWM (pulse width modulation) or chopper drive. We receive many questions about these drivers. For example, if a motor is rated at 5 V, many users wonder why they need to apply larger voltages. They also wonder why they are not getting increased performance even after changing to a PWM/chopper drive. Engineers sometimes forget about motor fundamentals like back EMF and electrical time constants when they are using stepper motors and drives. This results in an incorrectly configured stepper motor drive or driver and motor, which are starved for power (voltage and/or current) in the application.Microstepping can increase the resolution of a system, which smoothes rotation and prevents vibration and noise. However, problems will arise if incorrect voltage is applied to a PWM (pulse width modulation) or chopper drive. We receive many questions about these drivers. For example, if a motor is rated at 5 V, many users wonder why they need to apply larger voltages. They also wonder why they are not getting increased performance even after changing to a PWM/chopper drive. Engineers sometimes forget about motor fundamentals like back EMF and electrical time constants when they are using stepper motors and drives. This results in an incorrectly configured stepper motor drive or driver and motor, which are starved for power (voltage and/or current) in the application.

When an engineer does not understand the purpose of microstepping, a number of issues can arise. The main purpose is to increase smoothness of motor operation by leveling out the shocks of stepping, making operation more reliable. By misapplying microstepping, you can actually greatly decrease the available torque that the motor can produce. This usually requires a much larger motor than otherwise necessary. Those who don’t understand the proper use of microstepping opt not to use it, instead turning to servo-based systems, which add unnecessary levels of complexity and cost. Engineers also sometimes complete mechanical designs and then attempt to hide or dampen system vibration. When an engineer chooses an incorrect stepper, the motor won’t be able to move the load weight. Select the motor while considering not only load weight, but also the mechanism’s frictional properties.

Stepper drives always offer the cheapest solution, so use a stepper wherever appropriate. Remember these major considerations: First, does the system require position confirmation? Second: The wrong stepper drive can cause ringing, resonance, and poor low-speed performance. Third, during high speeds, stepper motors can whine. Because stepper drives have a high pole count, hysteresis and eddy current losses are also common at high speed; for these reasons, a stepper is not recommended for continuous operation above 2,000 rpm. Finally, because full current is needed to produce holding torque, step motors can get hot at a standstill.