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How to prevent step losses with Stepper Motors

How to prevent step losses with Stepper Motors
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How to prevent step losses with Stepper Motors - 1

FAULHABER Tutorial How to prevent step losses with Stepper Motors

How to prevent step losses with Stepper Motors - 2

How to prevent step losses with Stepper Motors The use of stepper motors is an excellent choice. However, a key concern is step losses. Step losses can be prevented or corrected in most instances. Stepper motors operate open loop. When a stepping motor does not operate correctly in a specific situation, the common conclusion is that either the motor or the drive electronics is faulty. The motor selection and the choice of the controller are critical. However, other factors contribute to step losses. The following points are important to examine for the analysis of step losses or...

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How to prevent step losses with Stepper Motors - 3

A. Stepper Motor Selection The first task is to select the right stepper motor The next step is to qualify the motor with practical for the application. For the best selection, those basic tests and verify if step losses occur during operation. theoretical rules have to be respected: Note that by construction, a stepper motor cannot lose only one step. If speed is low, it will lose a multiple of 1. S elect the motor based on the highest torque/ 4 steps (8, 12, 16 … Steps) and if the speed is high it speed point required by the application will stop rotating. In cases that less than 4 steps...

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How to prevent step losses with Stepper Motors - 4

B. Operation mode Depending on the type of motion profile, the analysis is different B1. Start-Stop operation Fig1. Start-Stop Frequency In this operation mode, the motor is hooked up to the load and and operates at constant speed. The motor has to accelerate the load (inertia and friction) within the first step to the commanded frequency. f Start/Stop Failure mode: Motor does not start Reasons Wrong motor, select a bigger motor If the motor oscillates from left to right, one phase may be broken or not connected Phase current is not appropriate Increase phase current , at least during the...

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How to prevent step losses with Stepper Motors - 5

Failure mode: Motor does not finish the acceleration ramp. Reasons Motor trapped in resonance frequency Increase the acceleration to go through the resonance frequency quickly Select start-stop frequency above resonance point Use half-stepping or micro-stepping Add a mechanical damper which can take the form of an inertial disk on rear shaft. Wrong supply voltage or current setting (too low) Increase voltage or current (it is allowed to set a higher value for a short period) Test lower impedance motor u se current mode control (if voltage driver is currently used) Reduce top speed Reduce...

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How to prevent step losses with Stepper Motors - 6

C. External Commutation Errors As explained earlier, a stepper motor will lose, by Phase 1 construction, a multiple of 4 steps (8, 12, 16 …. Steps). chronism. The motor stalls. If the number of missing directly with a 4 bit word. The shown driver represents a type which can be commanded without any additional control element commutation sequence delivered by the electronics. faulty and the investigation should be focused on the steps is not a multiple of 4 steps, the motor is not If the speed is high, step loss will lead to loss of syn- The commutation happens as follows (one phase ON...

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How to prevent step losses with Stepper Motors - 7

D. External events D1. Back driving D2. Increase of the pay load over time In some cases, the mechanism/load driven by the motor In some cases, the motor runs normally for a long during the movement wind up and return this energy period of time but lose steps after some time. In that back to the motor when the currents are switched off. case, it is likely that the load seen by the motor has This mechanism may be a reduction gearhead. changed. It can come from the wear of the motor bearings or from an external event. As the mechanism returns this energy back, the motor shaft may be rotated...

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