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DOCUMENTATION	Motors - General Information The Basics on Motors and Teleo Motor Controller Modules:   What are the characteristics of different motors? What are the important terms and abbreviations, and what are there meanings? I need a strong (or fast) motor. How do I figure out what what motor to get? Which Teleo Motor controller is approproate to my needs? Where can I go for more information?

AC MOTORS

· when power applied, turn in one direction at a fixed speed
· both reversable and non-reversable models available
· usually high voltage (110V AC and up)
· inexpensive and commonly available
· optimized to run at a fixed, usually high RPM.
· if the applied load is greater than the capacity of the motor, the motor will stall and possibly burn out
· MakingThings does not carry AC motors and controllers

 

DC MOTORS

· when power applied, turn in one direction at a fixed speed
· optimized to run at a fixed, usually high RPM.
· Torque is highest at the rated speed and lowest at low speeds
· speed can be varied if a PWM controller is added
· almost all can be reversed
· inexpensive and commonly available
· available in wide range of speeds and power.
· suitabe for turning, spinning, etc.
· not suitable for positioning unless some kind of position feedback is added
· if the applied load is greater than the capacity of the motor, the motor will stall and possibly burn out
· MakingThings carries DC motors and controllers

STEPPER MOTORS

· can not turn without a controller
· controller design is non-trivial
· inexpensive and commonly available, especially in salvaged computer equipment
· precise positioning possible by keeping count of steps requested
· Torque is highest at the full stop and decreases as speed is increased
· if the applied load is greater than the capacity of the motor, the motor not step, thereby making precise positioning no longer possible
· MakingThings carries stepper motors and controllers

 

SERVO MOTORS

· A DC motor combined with feedback for either position or speed
· A system with a motor, feedback, and a controller which constantly adjusts the position or speed to in reaction to the feedback is called a closed-loop system
· Hobby Servos include the entire closed-loop system
· Hobby Servos do not turn forever in any one direction. They are designed to turn between less than one and up to a few turns
· Hobby Servos require a special signal to tell them where to turn to
· Once told where to go, a Hobby Servo uses its built-in controller and feedback system to hold its position.
· When power is applied, in the absence of a signal, a hobby servo goes to its central position
· the signal to control a hobby servo is non-trivial to generate
· hobby servos can also be modified to turn continuously, in which case the control signal control speed instead of position
· MakingThings carries servo motors and controllers

 

BRUSHLESS DC (BLDC) MOTORS

· MakingThings does not carry BLDC motors and controllers
· MORE INFORMATION COMING SOON

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RPM - Rotations Per Minute. a way to specify how fast the motor turns.

PWM - Pulse Width Modulation. Power to the motor is rapidly turned on and off. By varying the ratio of "on" time to "off" time, the power to the motor, and therefore the speed, can be controlled.

BLDC - BrushLess DC motor. Commonly found in surplus computer equipment. Disadvantage: requires a controller and usually a position encoder to run. Advantage: very accurate speed control possible.

TORQUE - The "strength" of a motor. Measured in units of distance times units of weight, e.g. pound-inch or Newton-meter. A motor with a torque of 6 ounce-inch means that the motor can lift a weight of 6 ounces attached at a radius of 1 inch, or a weight of 3 ounces at a radius of 2 inches, etc.

FEEDBACK - A means of giving information from the mechanical system back to the control system, for example speed might be measured and sent back to the controller. The controller can then calculate an error signal, defined as the difference between the desired speed (the speed the controller is trying to achieve) and the actual speed (as measured ), and can take actions to reduce the error.

POSITION SENSOR - A means of providing an electrical signal that will indicate the position of some mechanical component. There are many ways of doing this e.g. a magnet can be attached to the device under question, and magnetic sensors (hall effect devices) can be used to detect when the magnet is near them. Or, a dark wheel with holes in it can be mounted between a light source and a light sensor. As the wheel turns the light is alternately allowed to pass or is blocked by the holes in the wheel. ( In this example the light could be visible or infrared). A potentiometer can also be used as a position sensor. In addition, if the time between the detections is meansured, the speed can be calculated.

QUADRATURE ENCODER - MORE INFORMATION COMING SOON

GEAR MOTORS - A motor combined with a gearbox to reduce the motor shaft speed and increase the torque.

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There are two approaches, and in the end the most practical is probably a combination of the two.

APPROACH 1 : USING PHYSICS AND MATH
You will need to specify how fast you want your object to move, and how much it weighs. Then, study the physics involved. This will tell you how much torque and
speed your motor will require. Depending on the application, you will probably require some form of gearing. Then, select a motor which meets your torque and
speed requirements, while at the same time fits within the Teleo voltage and current restrictions

APPROACH 2 : EXPERIENCE, OR TRIAL AND ERROR, COUPLED WITH RAPID PROTOTYPING
Rummage around in your junk box, or go to your local junkyard or electronic salvage or surplus emporium. Select a motor that your experience or intuition suggests might be in the ballpark. Consider voltage and current limits of the Teleo control system. If you don't need speed control you can use a relay and be completely free of any Teleo voltage and current restrictions. Consider also how the motor will be mounted.

Make a quick prototype of the mechanical part. Don't worry about how it looks, but pay attention to any mechanical issues. if the motor goes too far or too fast, will things break? Install a prominent "OFF" switch somewhere that will be easy to hit if things go bad. Is the frame strong enough to support the weights involved? Test the system. Is the motor barely moving the item or does it seem to be able to accomplish its task with no strain?

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MULTI IO MODULE / DIGITAL OUT, AND DIGITAL OUT MODULE:
Can control any DC motor up to 36 volts up to 2 amps, on and off only or with addition of the appropriate relay, any motor (AC orDC, low or high voltage), on and off if the motor is reversable, with the addition of the appropriate relay, can change direction.

MULTI IO MODULE / PM OUT:
Can control any DC motor up to 36 volts up to 2 amps, variable speed, one direction only with the addition of the appropriate relay, can change direction.

MOTOR CONTROLLER 2x2A MODULE:
Can control up to two DC motors up to 36 volts up to 2 amps, variable speed, both directions.

STEPPER MOTOR CONTROLLER MODULE:
Can control 1 bipolar 2-phase stepper motor or a hybrid motor that can be configured to run in this mode, up to 36 volts at 2 Amps per phase.

SERVO MODULE:
Can control up to 8 hobby servos.

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How to match Motor Torque Speed & Power, Wheels, and Winches:
http://pergatory.mit.edu/2.007/handouts/motorcalc/motorcalc.html

Some different ways to use a winch to move large loads:
http://www.mailbag.com/users/ragreiner/Winch.html

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