Powering the Motor

Now that the linear motor has been constructed, you will need to ensure that it works properly. The first activity explores how to power and manipulate the linear motor to make things move.

Guiding Questions:

• What happens when a battery is connected to the motor?
• What happens when the polarity of the battery is reversed?

Step 1

For this lab, you will need to following materials: linear motor, banana cables (or alligator cables), and a 9V battery.

Step 2

To power the motor, you will need to connect the banana cables to the motor, and then connect the cables to the terminals on the battery. Be sure to pay attention to the orientation of the cables to the battery terminals.

The battery has a negative and positive terminal. To start, connect the red cable to the positive terminal, and the black cable to the negative terminal.

What direction does the motor move?

Step 3

Now, flip the orientation of the cables. The red cable should be attached to the negative battery terminal, and the black cable to the positive battery terminal. What direction does the motor move? How does this differ from the previous experiment? What do you think is happening?

Articulated Figures

Example 1: Golfer

Example 2: Rocket Ship

Example 3: Shark

Operating the Motor with AC Power: Part II

The AC power source in the previous lab was created with a mechanical device. This type of alternating signal can also be created with a software app for a tablet or phone. WaveLab is an app that is illustrative of many software applications of this kind. It allows the rate at which the signal moves back and forth to be controlled, from one or two times a second to hundreds of times per second.

Step 1

Now you will power the linear motor using digital control. Most modern motors are infact controlled through digital control. If you are using the PASCO interface in your classroom, set it up along with your linear motor.

On the PASCO, there are two output jacks for the banana cables. Plug two cables into the jacks, and connect the other ends to your linear motor.

Step 2

Open up the SparkVUE software that comes with the PASCO interface. You will need to setup a new program. Select “BULD” and then select the Function Generator option. Your screen should look like the image on the left. Now, you will have two controls. Voltage and Frequency. Set the frequency to one hertz. Turn the function generator on, and adjust the voltage until the motor begins to move. Now adjust the frequency. What happens to the motor as you adjust the frequency?

Step 3

If you are not using the PASCO interface in your classroom, you can use an audio amplifier and software from your computer to drive the linear motor.

You will need to plug two banana jacks (with the ends cut and stripped to expose the wire) into the speaker jacks on the amplifier. Additionally, you will need to plug in an audio cable into the amplifier. The other end of the audio cable will be plugged into the speaker port on your computer.

Step 4

Connect the linear motor to the banana jacks from the audio amplifier.

You will need to connect the audio cable from the amplifier to your computer.

Operating the Motor with AC Power: Part I

The linear motor uses alternating current. Each time the current reverses, the magnet in the motor travels in the opposite direction.

Step 1

For this lab you will need to use the AC power source (pole reverser) and the linear motor.

Step 2

First, to ensure that the AC power source is working properly, you will need to hook it up to a current meter.

Step 3

Connect the banana cables to the analog curretn meter and AC power source.

Now turn the AC power source one full rotation. The current meter should detect a positive and negative current depending on the orientation of the battery. What do you notice as you turn the battery? Is your power source working as you expect?

Step 4

Now, gather your linear motor. You will use the AC power source to drive the motor.

Step 5

Connect the banana cables to the AC power source and the motor.

Crank the power source one full rotation. What happens to the motor? Is this what you expected? Experiment further with the power source and linear motor.

An Alternating Current (AC) Power Source

A direct current battery can also be used to produce an alternating current output by placing the battery into a frame that allows the battery to rotate. Each half-turn of the AC generator causes the polarity of the current to reverse.

Step 1

Fabricate Battery Alternator Parts

CAD Files: Download

Laser Cutter Files

There are three file formats (PDF, AI, SVG). Select the format that is compatible with your machine’s software. 

Laser Cutter Material

To build the motor, we use 1/8″ baltic birch plywood (source: Inventables). If you use a different material, be sure to adjust tolerances on the CAD file.

3D Printer File

There are two files in the downloaded package (9V-Plug and 9V-Cap). Open the 3D printer software and import the STL file, print both files. You will need one of each file per kit.  

Step 2

Begin assembling the parts to the base. The construction follows the same procedures as the linear motor.

Do not install the two center pieces that hold the solenoid tube. These parts are not necessary for this kit. The assembled base should look like the photo on the left.

Step 3

Now, you will need a paper clip for the next part.

Straighten out the paper into one long piece.

Cut two equal pieces of the paper clip.

Install these two pieces of iron into the base. There are two small holes that will fit these two pieces. If necessary, add a small dab of super glue to secure these iron rods into the base.

Step 4

For the next part, you will two pieces of stranded wire (red and black), and two banana jacks with the appropriate hardware.

Install the two banana jacks onto the base, just like the linear motor. Use the washer and nut to secure the jacks to the base.

Now, strip both ends of each piece of wire.

The stripped wire should look similar to the photo of the left.

Connect the black wire to the black banana jack and to one of the two iron rods. You will need to twist the stranded wire around the iron rod. Connect the red wire to the red banana jack and the other iron rod. Solder all four connections.

Step 5

Next, you will need a pair of plyers and a piece of iron rod.

Make one small bend at the top of the iron rod.

Make a second bend in the iron in the opposite direction as before.

Finally, secure the iron rod into the 3D printed part (9V-Cap).

Step 6

Now, grab another piece of iron rod and the other plastic part that was 3D printer (9V-Plug).

Secure the iron rod into the plastic part.

Finally, trim the iron rod and make a bend in it.

Step 7

Now you will need the 9V battery to complete the project. Attach the the 9V-Cap with iron rod to the end of the battery without the metal contacts.

To make the assembly easier, remove one of the wooden posts and slide the hole of the post through the iron rod.

Finally, attach the battery assembly back onto the base. It should look like the photo on the left.

Step 8

Grab the 9V-plug plastic part and attach it to the battery. You will need to guide it through the other wooden post to attach it to the battery.

You should now have the pole reverser fully assembled.

Building the Linear Motor (Cardstock Version)

A linear motor can be a gateway to exploration of topics that include electromagnetism, force and motion, mechanical and electrical waves, and sound and vibration. It also can provide a building block in design of kinetic mechanisms and art.

Fab@School Maker Studio was developed as a design tool to support the design process in Maker Spaces. It was developed through a public-private partnership between non-profit The Reynolds Center for Teaching, Learning, and Creativity, the educational software publisher, FableVision Learning and a number of educational collaborators that includes the Laboratory School for Advanced Manufacturing.

The design for a linear motor developed by Eric Yoder and Elizabeth Smalley has been incorporated into the Fab@School Maker Studio Ready-Made Projects library. This design supports fabrication of a linear motor with inexpensive materials such as card stock. The design can be printed on an inkjet printer and cut out with tools such as scissors. Another option is to use an inexpensive digital die cutter such as the Silhouette Portrait (cost approximately $150) to automate the process of cutting out the pieces. This makes it possible to quickly make changes to the design through a series of successive iterations that is at the heart of the engineering design process.

Materials & Resources

The following materials and resources are needed for the project.

• Fab@School Maker Studio
• Silhouette Die Cutter
• Inkjet Printer (Color)
• Cardstock (min: 6 sheets) 
• Scissors
• Glue stick
• Magnet Wire (32 AWG)
• Electric Spool Winder
• Iron (Coat Hanger)
• Permanent Magnet    

Step 1

Fab@School Maker Studio

Access Fab@School Maker Studio at www.FabMakerStudio.com.
Fab@School Maker Studio is a cloud-based program that can be accessed online using a web browser. Once you secure a Maker Studio account (available from FableVision Learning: http://shop.fablevisionlearning.com/fabschool-maker-studio-/fa/shop.detail/productID/2957/#.V-Fo65MrJZ0), you will be able to open and log into Fab@School Maker Studio.

From the Ready-Made Projects Menu Open the Linear Motor Invention Kit
The Linear Motor Invention Kit can be accessed through the Fab@School Maker Studio Ready-Made Project menu under 3D-Stuff. Once you have opened the Linear Motor Invention Kit, send the design to a color printer. Print the file at 100%. Do not scale or fit to page. This will require 8 sheets of card stock.

Step 2

Cut Out the Design Elements
If you do not have a die cutter, you can use scissors to cut out the design elements. If you have a Silhouette die cutter, you can send the Linear Motor Invention Kit to the Silhouette.

That icon will provide access to a dialog box, “Send to Cutter,” shown below. Once the Silhouette cuts and scores the design elements on each of the six sheets of card stock, separate the design elements from the card stock. (Or, if you do not have a die cutter, assemble all of the pieces that were manually cut out of the card stock using scissors.)

Step 3

Assemble the Motor Support Components: Part 1

The motor support components include a base and supports designed to hold a solenoid that is a key component of the linear motor. A solenoid consists of a tube, created with card stock in this instance, with many wraps of magnet wire around it. When an electrical current is sent through the solenoid, it generates a magnetic field that moves the motor back forth.

(A) Assemble the Solenoid Supports

Fold and glue (1) the two solenoid supports, (2) the end pieces that limit the movement of the motor, and (3) the solenoid support bar, as shown below.

When all five pieces (two solenoid supports, two end pieces, and the solenoid support bar) have been assembled, they will look like the illustration below.

(B) Attach the Solenoid Supports and End Pieces to the Base

Insert the two solenoid supports and the two end pieces up through the base as shown below. Glue the tabs on the bottom side of the base.

(C) Insert the Support Bar

Glue the support bar to the base and to the tabs attached to each end piece.

(D) Fold down the sides of the base and glue.

Step 4

Assemble the Motor Support Components: Part 2

(A) Fold the corrugation and insert in base, as shown below. Attach with glue or tape.

(B) Assemble the Top Piece.

Fold and glue the side tabs of the top piece to construct right-angle triangles, as shown below.

(C) Assemble the Side Pieces

Assemble the side pieces as shown below on the left. Once the side pieces are assembled, they should look like the photo on the right. 

(D)Attach the Sides and Top

Glue the sides to the base as shown below. Then glue the top to the sides.

Step 5

Assemble the Solenoid Tube

In addition to the four discs and the rectangular piece shown left and center below, you will need a 3/8” diameter magnet and a piece of scrap cardstock about 6cm x 6cm. The scrap cut from the center of the side piece in Step 5, g. works well for this (shown right in the photo).

Roll the cardstock scrap tightly around the magnet and secure with tape.

Roll the rectangular piece tightly around the magnet and the cardstock scrap. Secure with glue.

Glue the four discs to form two thick discs. Slide these discs onto the tube. The discs should be about 4 cm apart. Secure with glue.

Once dry, pull the cardstock scrap wrapped around the magnet out of the glued solenoid tube. Remove the magnet from the scrap. The solenoid tube is ready to be wrapped with magnet wire.

Step 6

Assemble Motor

The motor consists of a solenoid (magnet wire wound around a cardstock tube), a permanent magnet, and two motor rods (sections of a wire coat hanger).

(A) Construct the motor rod assembly.

The motor rods (sections of coat hanger) will be placed on either side of the permanent magnet. The motor rods are suspended from two supports attached to the top. Attach the supports to the motor rods by folding the bottom tab overtop of the wire as shown below.

Then secure the wire by folding long vertical tabs overtop of the tab. A wave that will project through a slot in the top is then attached. When the motor moves back and forth, the waves will also move back forth.

(B) Complete the motor. 

Place a permanent magnet in the solenoid. Then insert the solenoid between the two motor rods, as shown below, attaching the rods to either side of the permanent magnet. Because the metal of the coat hanger wire is ferrous, the magnetic attraction of the permanent magnet is sufficient to secure the rods.

Step 7

Final Assembly

The final assembly involves two steps. The boat and associated waves are attached to the top. Then the motor is placed on the motor supports to complete the construction.

(A) Attach the Boat

Attach the boat and second set of waves associated with it to the top, as show below.

(B) Insert the Motor

The motor is placed on the motor supports, as shown below. The wave pattern attached to the motor assembly projects through the top. When the motor moves back and forth, the waves also move back and forth.

Building the Linear Motor

A Linear motor is a simple electromagnetic device that is capable of moving in two directions.

Step 1

Fabricate Motor Parts

CAD Files: Download

Laser Cutter Files

There are three file formats (PDF, AI, SVG). Select the format that is compatible with your machine’s software. 

Laser Cutter Material

To build the motor, we use 1/8″ baltic birch plywood (source: Inventables). If you use a different material, be sure to adjust tolerances on the CAD file.

3D Printer File

There is a single file in the downloaded package (end-cap). Open the 3D printer software and import the STL file, print four end caps for the motor. 

Step 2

Assemble the laser cutter parts together to build the body of the motor. The pieces should press-fit together. A hammer can be used to tap in parts into the corresponding holes.

Press the spool holders and the end stops into the motor base.

Step 3

Finish the assembly of the motor body by attaching the four feet to the bottom of the base. Again, use the hammer if necessary.

At this point, the motor body assembly should be completed.

Step 4

Assemble the two banana jacks onto the motor base. There are two holes cut out towards the back that will fit the jacks. You will need to unthread the nut and remove the washer. Attach and tighten the nut and washer onto the base.

Here is how the banana jacks should look after you attach them to the base.

Step 5

You will now need to use the solenoid made in the previous unit. There should be two trough pieces that connect to the end of the solenoid. Gather all of these pieces.

Attach the two trough pieces to each end of the solenoid. These will guide the magnet in and out of the solenoid.

Finally, attach the solenoid assembly onto the motor base. The troughs should rest on top of the motor base as shown in this photo. Guide the two ends of the solenoid wire through the small holes located below the solenoid tube on the base. 

Step 6

You will need to solder the two solenoid wires onto the terminals of the banana jacks.

To make the soldering process easier, take each wire from the solenoid, remove the red insulation coating, and wrap it around the terminals as shown in the photo. This will keep the wire in place as you try and solder it.

Finally, solder the wire to the banana jack terminal.

Step 7

Gather the following materials: permanent magnet (1), 3D printed end caps (4), and a piece of coat hanger or iron rod. You will need to cut the iron rod into two pieces: 25mm and 15mm.

Use a hammer to tap the iron rod into the end caps.

Assmeble the motor’s armature by attaching each iron rod (with end caps attached) to each side of the magnet.

Step 8

Place the armature inside the solenoid tube. You may need to detach one of the iron rod assmeblies from the magnet, and then reattach it when it is inside the solenoid tube.

Here is a photo of the final motor assembly. You are now ready to test out your motor and make it move!