Washer launchers

This started as some old strobes rewired to make a "Thumper". Basically a thumper is a small coil connected in series with a camera or other type of strobe. When the strobe flashes it shorts out about 250 to 300 volts. By adding the coil in series you get a pulsed electromagnetic field that is quite powerfull. It is even capable of bouncing an aluminum washer an inch or two into the air.

The Washer launcher's electromagnetic coil is made from about 50 feet of #14 gague enameled wire wound on a reel removed from an old VHS video tape. The reel has to be reinforced or it will bust apart when trying to hold the coil. The Washer launcher runs directly off the 120 volt outlet and needs lots of insulation, so it's coil is covered with two layers of electrical tape.

Update - 1KV Washer launcher with flat coil

Well I finally managed to figure out how to wind a flat coil of about 30 feet of 14 gague enameled wire. I used a 3/4 by 3/4 by 1 foot board with a screw through its center to hold down the coil while I am winding it. I wound and then glued 3 to 4 turns each day. Tacks can be used to hold the wire in place while the glue is drying if needed. It has an inside diameter of about 1.5 inches and an outside diameter of 5 inches. It was designed to exactly fit an aluminum platter removed from a 5 1/4 inch hard disk drive. The disk now flies for over 30 feet vertically when the coil is used with my 900 volt washer launcher! Check out the video of this washer launcher in operation at You Tube

The 1KV washer launcher is going through yet another redesign. This time I am using an old microwave oven transformer. The high voltage winding has been center tapped for about 1000 Volts. Once it is rectified that should give about 1300 volts. I will need to manually stop the charging of the capacitors at about 1000 volts or risk blowing the capacitors. Initally all it did was blow fuses, I had to add a 470 to 1000 ohm 10 watt resistor to slow down the charging rate to save the fuses from blowing. The filament winding on the transformer has been doubled by adding onother few windings of wire to give it over 6 volts that then is rectified to provide power to run the cabinet fan. Not that a fan is needed but one was there so I figured it should be hooked up to something.

The 300 volt Washer launcher

The Washer Launcher (in the picture on the right) is a "thumper" that uses a huge SCR instead of the flash tube. This big SCR has to handle about 100 amps at 350 volts. The washer launcher uses about fifteen or more 330 uf, 400 volt capacitors in parallel for over 4000 uf total capacitance. The coil is only about 50 feet of #14 enmeled wire. When it fires it releases about 200 jules of energy into the coil. This can launch an aluminum washer about 12 to 14 feet vertically. The power supply used is a voltage doubler consisting of a 100 uf 400 volt capacitor and 1/2 of a 400 volt 6 amp bridge rectifier. The SCR is a 1538A73H05. I have no idea what its specifications are. However, if the connections to the SCR come loose, it will throw lots of sparks that fly for several feet!!

To prevent fireing while power is applied I used a 2 pole double throw relay. The first set of contacts are normally closed and applies power to the circuit. The second set of contacts is normally open and fires the SCR. This way the power is always removed before the SCR fires. Another improvement is to add 4 Neon bulbs in series with a 470 Kohm reisitor. When the neon's light up the capacitors are fully charged. The schematic omitted a .5 ohm 10 watt resistor and a 10 amp fuse in series with the power input from the power plug.

I have recently made a simplified thumper. This model may fry if you hold down the fire button, and does not discharge the capacitors if you forget to. Always push the fire button before opening it up and then short the capacitors before touching anything inside. Both of these modifications make it unsafe, but still usable. Also I am using another SCR. It is an IR 80RIA120, that is 800 volts at 120 amps! So far it has worked great. The coil has shrunk to 30 feet if 14 gague enameled wire. The washer has also grown. These days I am launching a platter from a 3 1/2 inch hard drive. Launch height is about 3 to 4 feet.

The first simpler thumper went up in smoke after about 3 days of use. The problem is the input capacitor feeds a dead short when the device is fired. The solution so far is to add a 5 ohm 25 watt resistor in series with the input as shown in the updated schematic. That limits the inrush current to 20 amps when the fire button is pressed. Although that is a lot of power the time is very short, but the resistor will get very hot!

The 600 volt Washer launcher

The next model uses four 7500 uF capacitors, and a voltage Quadrupler for 600 volts DC. These capacitors are bigger than the boxes that housed the older washer launchers. A new flatter coil has also been wound to hopefully work better with the hard disk platters. The new coil is about 20 feet of 14 gague wire. It is about 1/2 the thickness of a roll of electrical tape. Ever wonder how to make sure a hard drive is erased? In its first test runs it fried every diode on the voltage multiplier. Not to be outdone I added a relay to disconnect the voltage multiplier. After 2 successfull runs the relay was totally vaporized. One of the wires going to it even melted off.

I finally have a working 600 volt washer launcher. Currently I am using 2 RS605 bridge rectifiers that can handle 6 amps at 500 volts. Then in series I added a 25 ohm 25 watt resistor to limit the maximum current the diodes are exposed to. That was added after frying about 6 or 8 bridge rectifiers. The reverse current off the coil at 600 volts is enough to reverse charge the capacitors to about -170 volts! I suspect it could be more than -600 volts at the time of fireing because it vaporized a relay. Currently the soda can is flying about 3 feet into the air. I stopped using hard drive platters they hit the ceiling with enough force to do a lot of damage. Next I will try to CRUSH the soda can at 600 volts!

I tried crushing an empty soda can at 600 volts. I wrapped the can with a coil of 12 turns of #14 in the center. Then I charged up the capacitors to 600 volts and pressed the fire button. The results were not pritty. The wires to the coil melted off at the soldering connections. Sparks flew from some connections on the capacitor bank. The can was definately smaller at the center. However I could not tell if the shrinkage was from the magnetic field or from the mangled tangled remainders of the coil. Somehow I do not have the nerve to repeat that experiment. On the bright side the soda can on top of the coil has reached the ceiling. Did I forget to say everything survived the can crushing experiment but the coil?

The 900 volt Washer launcher

Coming up next will be a 900 volt washer launcher. I am planning on adding meters to monitor the charge/discharge voltage as well as the charge current. This model will use the 4 capacitors in the 600 volt model rearanged in series for up to 1200 volts. Next will be a voltage hexupler to deliver the 6 x 150 volts or 900 volts, likely to climb to 960 volts under no load. Will it survive its first test fireing? Stay tuned for more information.

IT WORKS!!!!!!!!! The only thing that has fried so far is the push button that fires the SCR. It went to a dead short after the first test fireing. I thought that I had lost the SCR but the SCR still works after a dozen fireings. For one of the test runs I used FIVE of the 5 1/4 hard drive platters on a coil on the floor. They hit the ceiling with enough force to leave 4 dents about 1 inch across, one of them was bent by the impact. In another test fireing I used one of the 5 1/4 inch platters at about 600 volts. The platter left a ring from it's outside edge on the ceiling.

The capacitor charging voltage meter I used for monitoring the voltage is a 1 ma meter, so it is installed in series with the 1 meg ohm bleeding resistor. That works out to 1 KV is equail to full scale movement. The top charge voltage is about 970 volts to be exact. I have also added the current meter, it peaks at about 3 amps while charging and pegs for a second during discharge. I have also used a 10 ohm resistor for a current limiter resistor instead of the 25 ohm resistor shown in the schematic. The current meter is a 1 ma meter in series with a 10 K ohm resistor and both are across the 10 ohm current limiter resistor.

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