Print PDF
Favorite
Email
Step 2General Details
Capacitors:
Connect the capacitors Via bare Solid wire and solder( Line up the negative with the negative!).
The capacitors should be rated 300VDC to 900VDC for best results, I recommend energy levels below 200J per stage or below 2000uF. The energy found in a capacitor can be calculated based on this formula:
1/2 x C x 1e-6 x V2
or
0.000005 x C x V x V
Where C is the capacitance in micro-farads (uF) and V is the Voltage the capacitor is charged to in Volts.
Coil:
Using the simulator or the previously test coils on step 3 determine your coil dimensions, gather the following supplies.
Here is a good video that shows you how to wind your coil:
How to Wind a Coil
-Bolt of an appropriate length and diameter
-Large diameter washers and nut to fit on the Bolt
-Electrical(usually black) tape or preferably super glue or epoxy
-Straw or paper to create a space between coil winding and the bolt
-Magnetic or Enamel wire
-I use Plexiglas( which can be found at Lowes or Home Depot) washers created via a hole saw and drill press. This allows you to super glue each layer to the plastic washers that way the coil is much more structurally sound when taken off the coil. If you choose to have plastic washer you can feed the starting wire through a grove or hole cut in back plastic washer, this aids greatly in winding.
Now, get your straw or piece of paper and cut it about 1-2mm longer than the desired length of your coil. Put the end washer(s) on the bolt and place the straw or paper on the bolt as shown in the picture, if the straw doesn't fit on the bolt simply cut it length wise.fit the remaining washer and nut on the bolt as shown.
Now feed the end of your magnetic wire though the center of your end washer and allow about 2-3 in of the wire to come out the other side. Wrap the wire that was put through the end bolt around the head of the bolt to secure it in place. Now start to wind the coil in a clockwise or counter-clockwise manner around the bolt. DO NOT switch from counter-clockwise to clockwise or vise versa, always wind in one direction around the bolt., otherwise your coil will not work .Continue to wind until you have reached the other end, secure the wire with your thumb and if you have tape tap the layer down tightly, if you are using super glue DO NOT glue the first layer, this will glue the wire to the straw or paper.
To make a second layer simply continue to wind, rotating in the same direction you started and making you way back to the other end of the coil on top of the first layer. Once you have reached the other side glue or tape the assembly and continue to wind in the same clockwise or counter-clockwise direction back and forth along the length of the coil. Wind the coil as perfectly as humanly possible and keep the wire as perpendicular to the bolt as possible.
Once you are done with your coil tape or glue the assembly as tight as possible and let it sit for few hours. Then, take the coil off the winder as carefully as possible and remove the inside of the straw or paper with pliers.
To Make the Guns grip open the plastic handle and hot glue in the roller switch so that the switch is triggered by, well, the trigger. Drill holes in the back and attach wires to the switch (1,3) and then put the wires through the holes. Close the Handle and if you can hear a click when you pull the trigger it should work.
RELAY
A relay has two working elements in it, an electromagnet and a mobile contact.
First a little Vocab:
NC-Normally Closed-When no current is applied to the electromagnet C and NC are connected
NO-Normally Open-When current is applied to the electromagnet C and NO are connected
C-Common- Connected to either NC or NO based on state of electromagnet
SPST- Single Pole Single Throw- Either NC or NO is included in this relay, not both
This relay will have 4 connections, Although some appear to have more, If the location of the electromagnet is unknown apply a 9V-12V source to each connection combination possible until a click is heard, this is the electromagnetic and when the relay is hooked up as in the diagram in the subsequent step the gun will fire when a proper voltage is applied to these connections again.
SPDT- Single Pole Double Throw- Both NC and NO are included in this relay(Shown in Picture below)
This relay will have 5 connections, Again If the location of the electromagnet is unknown apply a 9V-12V source to each connection combination possible until a click is heard, this is the electromagnet and when the relay is hooked up as in the diagram in the subsequent step the gun will fire when a proper voltage is applied to these connections once more.
For this Project either a SPST or SPDT Relay can be used, we only use the C and NO connection so a SPDT will have an unconnected Lead.
Opening the Relay will allow you to find these connections much more quickly, but put the cover back on when your ready to install the relay.
Also Below is a picture of the semiautomatic configuration in my PA-III-B.
Connect the capacitors Via bare Solid wire and solder( Line up the negative with the negative!).
The capacitors should be rated 300VDC to 900VDC for best results, I recommend energy levels below 200J per stage or below 2000uF. The energy found in a capacitor can be calculated based on this formula:
1/2 x C x 1e-6 x V2
or
0.000005 x C x V x V
Where C is the capacitance in micro-farads (uF) and V is the Voltage the capacitor is charged to in Volts.
Coil:
Using the simulator or the previously test coils on step 3 determine your coil dimensions, gather the following supplies.
Here is a good video that shows you how to wind your coil:
How to Wind a Coil
-Bolt of an appropriate length and diameter
-Large diameter washers and nut to fit on the Bolt
-Electrical(usually black) tape or preferably super glue or epoxy
-Straw or paper to create a space between coil winding and the bolt
-Magnetic or Enamel wire
-I use Plexiglas( which can be found at Lowes or Home Depot) washers created via a hole saw and drill press. This allows you to super glue each layer to the plastic washers that way the coil is much more structurally sound when taken off the coil. If you choose to have plastic washer you can feed the starting wire through a grove or hole cut in back plastic washer, this aids greatly in winding.
Now, get your straw or piece of paper and cut it about 1-2mm longer than the desired length of your coil. Put the end washer(s) on the bolt and place the straw or paper on the bolt as shown in the picture, if the straw doesn't fit on the bolt simply cut it length wise.fit the remaining washer and nut on the bolt as shown.
Now feed the end of your magnetic wire though the center of your end washer and allow about 2-3 in of the wire to come out the other side. Wrap the wire that was put through the end bolt around the head of the bolt to secure it in place. Now start to wind the coil in a clockwise or counter-clockwise manner around the bolt. DO NOT switch from counter-clockwise to clockwise or vise versa, always wind in one direction around the bolt., otherwise your coil will not work .Continue to wind until you have reached the other end, secure the wire with your thumb and if you have tape tap the layer down tightly, if you are using super glue DO NOT glue the first layer, this will glue the wire to the straw or paper.
To make a second layer simply continue to wind, rotating in the same direction you started and making you way back to the other end of the coil on top of the first layer. Once you have reached the other side glue or tape the assembly and continue to wind in the same clockwise or counter-clockwise direction back and forth along the length of the coil. Wind the coil as perfectly as humanly possible and keep the wire as perpendicular to the bolt as possible.
Once you are done with your coil tape or glue the assembly as tight as possible and let it sit for few hours. Then, take the coil off the winder as carefully as possible and remove the inside of the straw or paper with pliers.
To Make the Guns grip open the plastic handle and hot glue in the roller switch so that the switch is triggered by, well, the trigger. Drill holes in the back and attach wires to the switch (1,3) and then put the wires through the holes. Close the Handle and if you can hear a click when you pull the trigger it should work.
RELAY
A relay has two working elements in it, an electromagnet and a mobile contact.
First a little Vocab:
NC-Normally Closed-When no current is applied to the electromagnet C and NC are connected
NO-Normally Open-When current is applied to the electromagnet C and NO are connected
C-Common- Connected to either NC or NO based on state of electromagnet
SPST- Single Pole Single Throw- Either NC or NO is included in this relay, not both
This relay will have 4 connections, Although some appear to have more, If the location of the electromagnet is unknown apply a 9V-12V source to each connection combination possible until a click is heard, this is the electromagnetic and when the relay is hooked up as in the diagram in the subsequent step the gun will fire when a proper voltage is applied to these connections again.
SPDT- Single Pole Double Throw- Both NC and NO are included in this relay(Shown in Picture below)
This relay will have 5 connections, Again If the location of the electromagnet is unknown apply a 9V-12V source to each connection combination possible until a click is heard, this is the electromagnet and when the relay is hooked up as in the diagram in the subsequent step the gun will fire when a proper voltage is applied to these connections once more.
For this Project either a SPST or SPDT Relay can be used, we only use the C and NO connection so a SPDT will have an unconnected Lead.
Opening the Relay will allow you to find these connections much more quickly, but put the cover back on when your ready to install the relay.
Also Below is a picture of the semiautomatic configuration in my PA-III-B.
| « Previous Step | Download PDFView All Steps | Next Step » |
all the capacitors must be able to tolerate the emf output of the charger bank. the different capacitance values are not critical.
Most likely your coil is taking too long to discharge the caps. if you could decrease the resistance of the coil to around 0.3 to 0.1 ohms by using a thicker wire, you could vastly improve it's performance. for a 0.3 ohm coil I would recommend 4 to 5 caps of 120uF 330 v parallel. If nothing works buy 2 to 3 caps of 12000uF 63 volts. They worked the best with me because the amt of charge stored is high even though the voltage is low. Basically for a low power single stage coil gun the energy for each stage should be around 50 to 75 joules if your coil resistance is greater than 0.1 ohms
I get faster charging rates due to this.
You mentioned not using a capacitor with capacitance greater than 2nF. What would be wrong with using a supercapacitor, of say 1kF, besides the danger of handling such loads?
what should i do... should i decrease the number of capacitors, increase the voltage or change the coil. if the coil is the problem what size would you recommend?
look at the pa-iv schematic, it's got a good photogate circuit you can look at