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In this presentation, Lin Engineering will cover common stepper motor applications, issues that can arise within those applications, and stepper modifications that can help resolve those problems. Stepper motors are used in a multitude of applications in many different industries. Steppers can be applied to printers, robotics, security cameras, conveyor belts and aircraft in industries like automation, medical, surveillance, and renewable energy just to name a few. Each application is unique and the stepper motor must adapt to each situation. Due to the mechanical and environmental requirements from each system, a number of issues and failures can arise when stepper motors are introduced into such applications. Lin Engineering will discuss the root causes of issues like vibration, excessive heat, Back EMF, inertia mismatch and step loss that are seen while using a stepper motor. Lin Engineering will also explain how to resolve the problems through modifications and describe the effects of adding gearboxes, encoders, lead screws, vacuum and additional environmental modifications to a stepper motor. Why to Watch: Learn what modifications are required of stepper motors in certain applications. Learn what common issues arise from different applications. Learn what applications a stepper motor can be applied to. Learn how to resolve common application issues through stepper modifications.
Citation preview
Stepper Motors: Inside and Out
This webinar will be available afterwards at designworldonline.com & email
Q&A at the end of the presentation
Hashtag for this webinar: #DWwebinar
Before We Start
Moderator
Miles BudimirDesign World
Presenters
Jim NimitzLin Engineering
Tom LeLin Engineering
Stepper Motors: Inside and OutCommon Applications, Issues and Solutions
Presented by: Tom Le & Jim NimitzLin Engineering
Lin Engineering
• Started in 1987 as a consulting firm
• Founded by Ted Lin• Provides innovative
solutions to motion applications
• Manufacturing in Morgan Hill, CA and Nanjing, China
Industries & Applications
What We Will Discuss:1. Automation2. Medical 3. Aerospace and
Defense
Automation
What We Will Discuss:1. Common
Applications2. Insufficient Torque3. Optimizing Torque
Automation• As the Automation Industry expands, it
becomes more dependent on stepper motors
• Optimizing Torque and Smooth Motion from stepper motors is critical
• Common Applications Include:o Semiconductor Linear Stageso X – Y Table (2 Axis Movement)o 3D Printerso Cutting Machinery
AutomationSemiconductor Linear Stages:
AutomationCutting Machinery:
Automation – Linear Stages
• Used to give loads linear motion• Can be used in a horizontal or
vertical axis• Stepper motors must provide
smooth motion and high positional accuracy
• Higher operating speeds require steppers to maintain torque output
Insufficient Torque
• Magnetic Interaction between Coils and the Rotor
• Dynamic Torque decreases as Speed increases
Torque- Rotational Force
Insufficient Torque
• Larger motors generate more torque
• Greater Rotor Inertia and magnetic interaction
• Many applications are limited to a size constraint
Torque Case Study
Could Not Generate Enough Dynamic Torque at Desired Operating Speed
Customer’s Problem:
Optimizing Torque
Customized Motor Windings• Customized Windings for
Optimized Performance• Can Change Wire Gauge
and Turns per Coil to Tailor Motor Performance
Optimizing Torque
• Higher Inductance Lowers Dynamic Torque at Higher RPM
• Higher Inductance at Higher Speed Doesn’t Allow Current to Reach Rated Value
Optimizing Torque
Power In vs. Power Out• Can Optimize the
Winding for the Highest Motor Efficiency
Solution : Torque Case Study
By Optimizing the Winding, the Motor can Generate the Required Torque at the Desired Operating Speed
Proposed Solution:
Optimizing Torque
Gearbox and Pulley Assembly• Gearboxes and Pulleys
can be used to Produce more Torque
Medical
What We Will Discuss:1. Common
Applications2. Resonance3. Reducing Resonance
• Medical Devices require smooth motion and reliability from steppers.
• Therefore the motors must run accurately without interference.
• Common Applications Include:o Respiratorso Prescription Dispenserso Blood Analysis Machinery
Medical Industry
Medical IndustryPrescription Dispensers:
Medical IndustryAnalysis Machinery:
Medical – Respiratory Machinery
• Medical Device used to Remove Mucus from patient airways
• Requires high holding torque, accurate positioning, and position feedback
• Cannot overstep or miss steps
Resonance
When the frequency of a system’s oscillations matches the natural frequency
of the system.
Electrical Resonance
Stepper Motor Resonance:- At certain frequencies, the energy is
transferred to the motor body.- Natural step response is oscillatory
Resonance
• Every stepper system has unique resonance points
• Resonance can cause the system to: jitter, skip steps, lose accuracy, and even stall out.
• The system resonance leads to a loss of motor torque at defined motor frequencies; see the torque v. speed curve
Reducing Resonance
• Microstepping – Oscillations per step decrease greatly as steps become finer.
• Current: The motor can be overpowering. Many low speed applications will run smoother with reduced current (i.e. Lower the dT/dθ, torque stiffness)
Reducing Resonance
R-Winding• Created to reduce noise
and vibration for lower-torque applications
• Designed to eliminate the one-phase on position
Reducing Resonance
Mechanical Damping• Inertia Damping • Friction Damping,
Flange-mount damper
Electrical Damping• Driver Settings,
Microstepping• Special Windings
Reducing Resonance
Inertia Damper• Contains an inertia
body and elastomeric material
• Counters the effects of inertia
• Suppresses vibration
Aerospace and Defense
What We Will Discuss:1. Common Applications2. Environmental
Contamination3. High and Low
Temperatures
• Require rugged, long lasting and high performance motors that can withstand harsh environments
• Lin Engineering provided motors used in the B-2 Stealth Bomber
• Exampleso Satelliteso Ground Vehicleso Targeting Systemo Aircraft Ventilation
Aerospace and Defense
Heat Generation
Copper Loss:• Interaction between
current and resistance of the winding creates heat
Iron Loss:• Related to the
magnetic field interactions
High & Low Temperature
• Standard Motors (Class B)
• Temperature Classes
°C °FA 105 221B 130 266F 155 311H 180 356
Temperature Tolerance Class
Maximum Operation Temperature Allowed
High & Low Temperature
High Temperature• Bearing Grease, Teflon Leads,
Class H/F Insulator and Magnet Wires, Special Magnets
Low Temperature• Bearing Grease• Teflon Leads
Environmental Protection
IP Rating ( IP XX) • Protects Motor
Against Solid Objects and Liquids
Environmental Contamination
• Motors subject to rain need protection from liquid or solid ingress
• Moisture in between the rotor and stator can lead to rust
• Particles within the air gap can cause the motor to lock up
Wash Down Applications
Environmental Protection
IP 65• Protected Against Dust,
Low Pressure Jets of Water
• Better Protection from Environmental Elements
Environmental Protection
IP X7• Protected Against Dust;
Submersible in Depths of 15cm to 1m
• Better Protection from Damaging Environmental Elements
Aerospace and Defense – Aircraft
Ventilation
• Steppers require protection from the environment (i.e. rain, moisture, pressure)
• Must operate in extreme temperatures; high and low
Environmental Protection•
Thank You!
Tom Le: Applications [email protected]
Jim Nimitz: Sales Engineer [email protected]
Tech Support: 408-919-0200
Questions?
Design WorldMiles [email protected]: 440.234.4531Twitter: @DW_Motion
Lin EngineeringTom [email protected]: 408.919.0200 ext. 457
Lin EngineeringJim [email protected]: 408.919.0200 ext. 233
Thank You This webinar will be available at designworldonline.com
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