Electrical Engineering/motor switch



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What is the motor voltage and current?  If it is 115VAC, then it looks like connecting AC hot (black) to the motor's red wire would make it rotate one way, and connecting hot to the blue wire to rotate the other way.  But if the motor is rated lower than 115VAC, then additional circuitry would be needed.

It has 120 VAC, 60 HZ, 4.5 amps on the motor.  As I noted, it did operate it in both directions, so I want to be able to control that more precisely with the rocker switch.  I hope I can just eliminate the circuit board that came with it, as I assume it is all about control (this is a surplus garage door opener.)
So the DPDT switch should work if I can connect it properly.


If the motor is rated 120VAC, then you should be able to eliminate the PCB and use a double throw switch.  The problem will be to find a switch that is rated for high enough current. Since the motor takes more current when starting up, I would recommend a switch rating of at least 10A at 120VAC.  The switch can be a rocker as you stated (using three of the six terminals), or can be a single pole double throw (SPDT) momentary toggle switch with center off.  (Or a double pole double throw (DPDT) momentary toggle switch with center off, and use three of the six terminals.)

I'll call the three terminals: center pole, contact A, and contact B.  (If you check with an ohm meter, you would find that the center pole connects with contact A when the switch is in one momentary position, and the center pole connects with contact B when the switch is in the other momentary position, and there is no connection between the center pole and either contact when the switch is in the center position.)  

The hot wire (black) would go to the center pole.  The blue wire to contact A, and the red wire to the contact B.

Make sure the switch rating is high enough, as I stated, or the switch may melt, or weld its contacts.

Hope this helps!


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Dave Nyce


I have been an electronics engineer for many years. I can answer questions on analog and digital circuits and my specialty is sensors.


I am the inventor on 27 US patents, and also some foreign ones. Developed sensors for many years. Licensed private pilot (airplane and rotorcraft), have HAM radio license. I'm not an expert in computer networking.

AAAS, Certified Control Engineer, (former UL Advisor for Intrinsic Safety), Benefactor member of NRA. Life member of the following: Experimental Aircraft Assoc., US Parachute Assoc., National Trapper's Assoc., Apex Masonic Lodge #584, Scottish Rite of Raleigh, NC, Academy of Model Aeronautics, Grass Roots North Carolina, NC Rifle & Pistol Assoc. Member of the following: Aircraft Owners & Pilots Assoc., US Hang Gliding & Paragliding Assoc., Tripoli Rocketry Assoc., Apex Historical Society, The Planetary Society, USA Volleyball, Shriners of North America, York Rite Masons, National Space Society, Benevolent and Protective Order of Elks, and the Precision Aerobatics Model Pilots' Assoc.

Books: "Magnetic Displacement Sensors" section in: Measurement, Instrumentation, and Sensors Handbook, CRC Press, 1999. ISBN 0-8493-8347-1; "Magnetostrictive Sensors", "Hall Effect Position Transducers", & "Strain Gage Accelerometers" in: Instrumentation and Control, a Mechatronics Handbook, John Wiley & Sons, Inc. NYP; “Magnetic Level Gauges” chapter in: Instrument Engineers’ Handbook - Measurement & Analysis, 4’th Edition, CRC Press, 2003; Author of the book “Linear Position Sensors, Theory & Application”, John Wiley & Sons, 2004; “Electronic Transmitters”, “Linear & Angular Positioning of Machinery”, and “Inerting Systems” sections in: “Instrumentation Engineers’ Handbook – Process Control, 4’th edition, (2005); “Hazardous area classification and management”, and “HART Networks” sections in the book: “Instrumentation Engineers’ Handbook – Digital Process Networks and Software, 4’th edition, publication in 2011 Magazines: Magnetostriction-Based Linear Position Sensors, SENSORS magazine, April, 1994: Tank Gauging Advances, Fuel Technology & Management, January, 1997: Magnetostrictive Position Sensors, Measurements and Control, September, 1998; A Moment in Positioning, PTDesign, February, 1999; Magnetostrictive Position Sensors (update), Measurements & Control, September, 1999; Position Sensors for Hydraulic Cylinders, Hydraulics & Pneumatics, November, 2000; Magnetostrictive Linear Position Sensors, Fluid Power Journal, April, 1999; Sizing & Applying Magnetostrictive Linear Position Sensors, Motion Systems, Feb., 2002; Position Sensors in Medical Applications, ECN, May 15, 2002; Featured in “Level Sensors Go Floatless”, Machine Design, May 8, 2003; "Guitar Man" feature article, The Pelican Post, Oak Island Press, Oak Is., NC, Winter 2005; The LVDT: A Simple and Accurate Position Sensor, SENSORS magazine, August, 2005; "Model Airplane Day!", FLYING MODELS magazine, September, 2006; “Kids Having Fun!”, Half-A Flyer magazine, January, 2012

BSEE, MBA, Management by Objectives - Honeywell, Total Quality Management - MTS Systems Corporation, Looking Glass Management Workshop - Center for Creative Leadership, Motion Control Systems - Western Michigan University, College of Engineering, Organizational Excellence - University of Cleveland, Finance for Executives - Sloan School of Business, MIT.

Awards and Honors
Vaaler award, EDN magazine, "Inerting for Safety", 1987 Listed in Who's Who in Engineering, in the South, in the World. "Total Quality Management" medal awarded by MTS Systems Corporation 1991 "Best Sequel" award for the video production: "For Engineers Only" at the MTS national sales meeting, Las Vegas, 1998 (written and directed by David S. Nyce) Voted "Most Effective Leader" at Center for Creative Leadership: Looking Glass, Greensboro, NC 1995 Silver Award for New Technology at SENSORS EXPO, in Chicago, 2001 for SEF Liquid Level sensor MTS Circle of Innovators award, 2003 Elected Master of Masonic Lodge #584 , Apex, NC, 2005 "Gold Honour Award" for outstanding service in York Rite Masonry, by the York Rite Sovereign College of North America, August 22. 2007 Board of Directors: WaaRev Sensors, and the Apex Historical Society Maynard Pearson House Plaque hanging in the Masonic Fellowship Hall, for Outstanding Service and Dedication to Apex Masonic Lodge #584, Apex, NC

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