Electromagnetic Actuator-Solinoid Noah A. Sundberg ECE 5320 Mechatronics Assignment #1
Outline • Resources • Related Web Pages • Introduction • Major applications • Specific applications and uses • How it works • Principles Behind Solenoids • Example 1 • Specifications • Selecting a Solenoid • Limitations
Resources • Mechatronics Handbook, Robert H. Bishop, CRS Press • Integrated Publishing www.tpub.com/content/doe/h1013v2/css/h1013v2_166.htm
Related Web Pages • How Stuff works • science.howstuffworks.com/electromagnet3.htm • Integrated publishing • www.tpub.com/content/doe/h1013v2/css/h1013v2_166.htm • Jewel Instruments • www.wpiinstruments.com/solenoids/theory.htm
Introduction A solinoid is the most common type of electromagnetic acutuators. A solinoid consists of an Iron core surrounded by coiled wire. When the coils have current flowing through them they create a magnetic field that pushes or pulls on the iron core depending on what direction the current is flowing.
Major Applications Solenoids are used in • Valves • Water valves • Gas valves • Relays • Power relays • Switches
Specific applications and uses • Automatic Door locks • Office Equipment/ Printers • Electric/ Electronic Locks • Photographic/ Optical • Medical Instrumentation • Coin and Bill Changers • Cash Drawers and Automatic Teller Machines
How it works Principles Behind Solenoids -Lorentz’s law of electro magnetic induction states that a magnetic flux (theta) exists due to a magnetic field The fields strength is H and the flux density is B and are related by the magnetic permeability of the substance that the field is in.
How it works (continued) Principles Behind Solenoids-Continued -Faraday’s Law of Electromagnetic Induction states that a change in the electromotive force (emf) or Voltage across the conductor causes a change in the flux. There for current creates magnetic flux as is shown in fig 1(Mechatronics Handbook) Fig 1
How it works (continued) Principles Behind Solenoids-Continued -As shown in figure 3 and 4 (found in the Mechatronics Handbook) in a solenoid utilizes these characteristics to cause a B field in one direction The strength of the field depends on the length of the solenoid (L) the number of turns (N) the magnetic permeability u and the current i Fig 3 Fig 4
How it works (continued) Example 1 –Valve A spring maintains the valve in its closed or open position. When a current is produced the coils around the core Produce a magnetic force That pushes the valve to the Open or closed position When the current is stopped The force is removed and The valve moves to its original Position. The set up of this Can be seen in figure 1(from www.tpub.com/ content/doe/h1013v2/ css/h1013v2_166.htm) Fig. 2
Specifications • current driving solenoid • Initially open or closed • DC or AC • Number of Turns • Voltage maintaining the core in position
Selecting a Solenoid Many mechanical, thermal, and electrical constraints should be considered when selecting a solenoid. • Force requirements • Electrical requirements (current driving actuator etc.) • Duty cycle • Maximum envelope dimensions • Temperature extremes • Termination requirements • Dimensions
Limitations • Current flowing through coil • Dimension • Voltage across the coil • Distance the armature needs to move
Where to Buy • WellGrow industries Corp. www.fittings.com.tw • Command Alarms www.commandocaralarms.com/solenoids_actuators.asp • Saia Burgess www.ledex.com/df/LXGOG/index.html • Alltronics.com www.alltronics.com/relays.htm • Penn+Giles www.pennyandgiles.com/products/products.asp?strAreaNo=402_12 • Corrosion Fluid Products Corp. www.corrosionfluid.com/Products/valves/actuators.htm