Stepper motors are used in industries for manufacturing and other requirements. Read on to learn more about how to check if a stepper motor is working!
Stepper motors are extensively employed in a wide range of industrial and business uses, such as 3D printers, robotics, CNC machines, and automation systems. This post will examine the working of the stepper motor and tips to check and test it when it is not working.
When inspecting a stepper motor system, it is important to check every component that may have an impact on the system's operation. The system as a whole that directs the stepper motor in its motion should be understood first. The motor control unit (pulse generator) can be removed from a stored data type driver as it has an integrated controller that saves motion data and settings.
Tips to Debug and Test the Stepper Motor
Here are the tips to test and debug the stepper motor and check if it is working properly.
1. Bench Setup for Stepper motor testing
Purchase a current probe. Stepper motor audio noise sources can be troubleshooted with the use of a current probe. To ensure an accurate, current measurement, remember to zero the probe. Make use of a bench supply with sufficient current capacity. When driving excessive motor currents, the bench supply's current limit may restrict the supply-rail voltage. Make sure the supply you choose and the current limit you specify are sufficient for the motor you are testing.
2. Identifying the Stepper Motor Phases with a Digital Multimeter
Let's imagine you discover an unidentified stepper motor in the laboratory, and you want to test a bipolar stepper driver quickly. The motor leads are unmarked and the motor datasheet is unavailable. One method of determining whether terminals are part of the same stage winding is to use a DMM to gauge conductivity or validate continuity.
3. Current Regulation Schemes in the motors
Stepper motors can produce audible noise for a variety of reasons. Occasionally, the step rate might be at the mechanical system's resonance frequency, which exacerbates noise. When troubleshooting stepper motors, the first thing to do is to look for abnormalities in the current waveform.
It is frequently possible to lower audible noise and enhance the overall appearance of the present waveform by adjusting the depletion mode or other variables. Because smaller is quieter, the current regulation scheme, often referred to as the decay mode, and the microstrip size may be the cause of additional variables.
4. Check the current profiles of Stepper Motor
To accomplish micro-stepping for increased accuracy and reduced noise when operating a stepper motor, most stepper drivers employ a current regulation technique. Microstepping techniques use discrete step levels to regulate the current to approach a sinusoid.
In contrast to brushed-DC motors, stepper motors do not have an inrush current upon motor startup, nor do they experience a spike in current during a stall condition. This is so because stepper motors lack a mechanical commutator. Rather, stepper motors require electrical commutation, which is achieved by supplying the two-phase cables with regular current waveforms that have phase angles that range by 90 degrees.
The phase currents have a square wave appearance when full stepping is used. The phase currents have sinusoidal characteristics while microstepping. Most integrated stepper drivers use current regulatory approaches for both micro-stepping and full-stepping.
Stepper Motor Driver Fault Reporting
For stepper motor drivers, popular motor-driver protection features include undervoltage lockout, overcurrent protection, and overtemperature shutdown. These attributes could be useful in determining the root cause of a specific problem while debugging a motor system.
● A motor driver source rail voltage decrease from series susceptibility in the power supplying or routing, insufficient isolation or mass capacitance, bench power clamping mode, or inadequately designed power circuits can all result in an Undervoltage lockout.
● If there is a contract between the motor-driver leads or from one of the terminals to the supply or ground, overcurrent protection may trip.
● When the motor driver runs high currents for extended periods or when the surrounding environment's temperature rises too high, overtemperature protection may be activated.
Certain drivers might be equipped with extra safety features like open-load monitoring and overvoltage protection. The functioning of these attributes will be explained in the driver datasheet. A fault-reporting pin is often present on motor drivers, signaling the occurrence of a fault. You may inspect this pin while troubleshooting to get the oscilloscope to display a screenshot. Make sure you verify the currents and voltages.
In Conclusion - Check Out the other Testing Tips
Unmounted motors have a tendency to shake a lot and "jerk" when they accelerate or decelerate rapidly. This demonstrates Newton's third law in action: when the rotor moves in one direction, the stator spins in the opposite direction due to an equal-and-opposite reaction torque.
● To reduce vibration from the motor moving on a hard surface, place the engine on top of a foam cushion or a different soft material. Use a vice, tape, or clamps to secure the motor to prevent any jerky movements.
● When operating high-power motors, which can get extremely hot after extended periods of usage, place the stepper motor on a heat-absorbing surface, such as a heatsink.
● If the motor is not under any other load, attach tape to the motor shaft so you can quickly identify which way the motor is spinning.
● When the motor is attached to an unused motor driver, do not turn the motor shaft. When the motor experiences large currents or voltages, it will operate like a generator, which could harm the stepper motor or the power source.
● When the motor-driver signals are enabled, do not connect or unplug the motor from the circuit board connector. If you do this, there may be obvious sparking and possible harm to the board and motor. You may burn a finger.
You should find these recommendations useful while troubleshooting your systems' stepper motor drivers. Visit Smooth Motor Solutions for additional advice on debugging motor drivers.
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