What do candidates on the Motion Control training course actually do?
The course begins by looking at ac inverter drives and provides an extensive understanding of the relationships between speed and torque and voltage and frequency of industrial motors.
The course notes are quite extensive and explain how ac drives create the PWM output signal as a method of simulating a variable-voltage variable-frequency sinewave, without getting involved in the underlying theory. For example, we would look in detail at what signals are produced at the output of a drive, but only very briefly at how the remainder of the electronics work. Some sample pages from the course notes give an indication of this approach:
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Page 7 of the Motion Control training course notes, describing how torque and speed are related |
Page 27 of the Motion Control training course notes, showing what the PWM waveform generated by electronic motor drive units looks like |
Page 48 of the Motion Control training course notes, describing the typical faults developed in the drive output stages and how to find them |
Candidates on the Motion Control training course then have the opportunity to configure an industrial drive unit connected to a real three-phase motor on one of our specially-designed training rigs. Each of the major manufacturers of drive units are represented. Candidates can explore how changing the parameters of the drives alters their behaviour at start-up, while running at various speeds, and at switch-off. All of this can be done in perfect safety - an opportunity they are unlikely to have with the drives they have in their workplaces.
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The Omron training rig used on the Motion Control training course: a real industrial drive connected to a real 3-phase motor so that candidates can explore the effects of changing parameters on the Omron drive |
The Siemens training rig used on the Motion Control training course: a real industrial drive connected to a real 3-phase motor so that candidates can explore the effects of changing parameters on the Siemens drive |
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The Mitsubishi training rig used on the Motion Control training course: a real industrial drive connected to a real 3-phase motor so that candidates can explore the effects of changing parameters on the Mitsubishi drive |
The Allen Bradley training rig used on the Motion Control training course: a real industrial drive connected to a real 3-phase motor so that candidates can explore the effects of changing parameters on the Allen Bradley drive |
Candidates use various sorts of test equipment throughout the course. Standard digital multimeters are used to test the serviceability of a drive's power module (the most commonly failing part in any drive unit), tachos are used to measure the motor speed accurately, current clamp meters are used to monitor the current flow to the motor and a digital oscilloscope is used to analyse the drive's PWM output waveform.
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The current probe used on the Motion Control training course |
The digital storage oscilloscope used on the Motion Control training course |
The electronic tacho used on the Motion Control training course |
Safety issues are, of course, paramount considerations, and the dangers of incorrect parameter settings, the dangers of electric shock whilst working 'live' and making measurements (particularly with regard to the high energy capacitors found inside inverter drives), as well as the physical dangers associated with unexpected motor movement are all covered on the course, as are the important issues of emc and installation earthing and suppression components.
On the second day of the course we move onto Steppers and Servo drives and we begin by analysing the range of motion control methods commonly used in industry - positional control, speed control and torque control. The various applications of these control methodologies are discussed, by describing the common requirements of packing machines, robots, palletizers etc. We look at how servosystems work, their maintenance issues and what typically goes wrong with them. We look at the particular problems of regeneration, causes of servomotor bearing failure, the effects of mechanical shocks on servomotors etc.
The following are some extracts from the course notes, showing how trapezoidal characteristics are designed into servomotors, how brushless motor drives work and how stepper motors work.
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Page 11 of the course notes for the Motion Control training course, showing how trapezoidal characteristics are designed into servomotors |
Page 17 of the course notes for the Motion Control training course, showing how brushless motor drives work |
Page 33 of the course notes for the Motion Control training course, showing how stepper motors work |
The candidates practice configuring and tuning an industrial servodrive using PC-based software, programming it to respond to signals from a remote control unit, which simulates HMI or control panel inputs to the drive. Candidates then practice making the servomotor start, stop, ramp up and down and run at various speeds.
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Candidates on the Motion Control training course use an ac brushless servomotor to explore the operation of industrial servos |
We use a remote control unit to control the servodrive on the Motion Control training course |
Candidates on the Motion Control training course use an industrial servodrive to investigate the various motion control parameters that can be changed and also configure the drive's responses to inputs from the remote control unit |
We then look at the range of stepper motors commonly used in industry, looking at how they work and where and why they would be used in preference to servomotors (cost factors, reliability issues etc). The various applications of stepper motors are discussed (print registration, etc). We look at how stepper drives work, the complex electrical connections required, their maintenance issues and what typically goes wrong with them. We discuss the particular issues of slewing, resonance and other problems.
The candidates use a specially designed stepper drive unit (allowing them to explore the uses of unipolar, bipolar and microstepping drive types) which can run at extremely low speeds so that they can actually see the drive signals sent to the stepper motors in the various different modes of operation (half-step, microstepping, wav etc). This aids in their understanding of stepper motors and the associated drive units.
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Candidates on the Motion Control training course use an industrial hybrid stepper motor to explore the operation of industrial stepper motors |
We use a specially-designed stepper drive unit with unipolar, bipolar and microstepping outputs, capable of running at very low speeds so that candidates on the Motion Control training course can see the signals produced by the drive in half-stop, microstepping and wav drive modes |
Candidates on the Motion Control training course use an optical tacho to measure the speed of the various motors used on the course |
If you would like to see some of the equipment used on the Motion Control training course for yourself, then please call us to arrange a visit to our offices in Kent. Alternatively, we can visit you anywhere in the British Isles.
