Type Iii Capacitor Inverter

OPTIONAL: Here is another way that you can make a high voltage inverter. Can be done mechanically or by using SCR's or Transistor.

To start; Instead of connecting and disconnecting capacitors in series as you may have seen in our type II Capacitor Inverter, In this new method you simply keep all caps connected in series as shown in figure #1. Fig. #1 is to help you get an understanding of how it works. The positive and the negative brushes slide over the contacts, moving together, creating a 24 VDC charge in each capacitor. For this simple experiment you will need to connect 6 - 50 Volt x 2200 or 25,000 uf capacitors together in series. ( solder all connections.)

Now tape down the caps flat onto a table top, Now cut 12 pieces of thick or thin ( thick is best! ) copper or aluminum to 1 1/2" x 3/4" squares and tape them down as shown in figure #1. Now solder your wire to the contacts and the caps as shown. Now using rubber gloves place the positive ( 16 gauge wire automotive type ) A Brush onto the first + contact and the negative B brush on the negative contact Now slide wires down the rows at the same time and at the same speed to charge each capacitor at 24 VDC. Slide and charge all the way to #6 cap. So you have now charged all caps and your DC volt meter should now read 144 VDC. ( Be careful not to touch, it can KILL! Use rubber gloves. )

Now at this point no load is connected. Always connect load or a 120 VDC cap bank x 25,000 uf AFTER YOU HAVE CHARGED CAPS, To avoid large sparks that can burn up your contacts. So again after you charge 144 VDC cap bank you then use a magnetic reed switch to turn on load.

144 VDC Output <4

A and B brushes move at the same time, moving all the way to the right to #6 cap and a little past #6, and if you will picture a magnet connected to your wrist that will then switch on the magnetic reed switch to power the load or charge your 120 VDC cap bank. Reed switch rated at 5 to 10 amps. Now if you will picture the contacts on a round stationary piece of plywood board and a rotor arm that turns with the brushes on it. to make contact with the cap contacts.


Below is a crude mechanical way to replace the relays if you are on a very tight budget.

Now as #7 rotor arm moves counter clockwise, it moves the contact brushes over 1 & 2 and so on. this all happens at a high rpm. ( You can try with lower Rpms to meet your needs.) The #4 brush is actually a set of brushes with 2 round commutators, the same commutators you would see in a AC motor, ( Not a DC motor!) the 24 VDC from the batteries travels through the #4 set of + and - brushes and travels through the 2 separate round commutator contacts, up through the 2 wires, through the brushes and onto the stationary contacts. Then to the capacitors charging them at 24 VDC each = 144 VDC. The commutator can be simple, using a 2 washer's a plastic spacer to protect from shaft, and some epoxy glue. or place a flat type onto the moving rotor arm.

Front View Of washer

Front View Of washer wood

Shaft wood


Metal Washer Commutators

DIY Battery Repair

DIY Battery Repair

You can now recondition your old batteries at home and bring them back to 100 percent of their working condition. This guide will enable you to revive All NiCd batteries regardless of brand and battery volt. It will give you the required information on how to re-energize and revive your NiCd batteries through the RVD process, charging method and charging guidelines.

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