How to build a 24V/1400 VA dc to ac power inverter with an auto-battery charger

Recently I have been receiving requests on how to build a 1500 VA inverter I can't remember the number of times and So here I suggest a very simple circuit which you can sit down and complete in about 4 hours.The circuit uses commonly available parts.The main advantage with this inverter is that it contains an internal change over relay.This makes it posible to run it directly on the utility line. Obviously you need to have some knowledge in electrical or electronics to do this project. Alternatively for just 12 dollars I can send you a detailed construction manual as well as my book titled "all about DC to AC power Inverters". If you trust your skills,then carry on.Rest assured this circuit works well as described and for your information,I have built several inverters using this circuit and they all work fine up to today

Instructions

Difficulty: Moderate

Things You’ll Need:

• 2000 VA transformer probably from a stabilizer.The transformer can be of the toroidal or ordinary.
• NE555 Popular timer IC
• CD4027 JK flip flop.
• Matrix circuit board
• IC holders for NE555 and CD4027.
• TIP35C x 22 pcs
• BF422 x 2 pcs
• MJE 350 x 2pcs
• IN4007 x 3 pcs
• 6A1 6amps diodes x 10 pcs
• Large aluminum heat sinks x 2 pcs
• LM7805 x 1 pc
• 3 pole double throw relay x 1
• a couple of resisters and capacitors as shown in the schematic

1. With a little modifications, this inverter can actual out perform most inverters on the market today.This design is quite simple and uses a popular timer IC NE 555 configured to run at approximately 100 Hz. R1 is used to adjust the out put frequency of IC2. The CD 4027 is JK flip flop connected in master slave mode. The output of IC 2 (NE555) is broken down into two opposite pulses of 50 Hz each.
2. The fixed voltage regulator 7805 is used to power the oscillator circuit and should be mounted on a suitable heat sink.
3. Transistors TR1, TR2, TR3 and TR4 are pre-amplifiers. Their function is to raise and buffer the output signals from the IC1 (CD4027)Transistors TR5 and TR6 are driver transistors and should be mounted on a suitable heat sink together with the main out put transistors TRX to TRX2. TRX and TRX2 simply represent an array of 10 transistors each.Diodes D2 and D3 prevent negative voltages from reaching the bases of driver transistors TR5 and TR6
   Diodes D4to D5 protects the output transistors against back e.m.fs generated during operation and are also used during battery charging. D1 protects the oscillator against accidental wrong polarity
4. The Inverter /charger Transformer should be rated 20-0-20 volts AC.If you are using a stabilizer transformer,carefully remove the secondary coil and replace with a bigger gauge At least SWG 10. Use bifilar winding for best results.In the construction manual all this is indicated.

Tips & Warnings

• You can include in a voltage comparator circuit to control a relay in series with the oscillator supply. This way should the battery voltage fall below 10.7V (at 10.7 a battery is considered to be fully discharged), then circuit will automatically switch off your inverter
• For initial testing remember to use an adjustable DC power supply with a limited current.Should there be any mistake your components will survive.
• When you are satisfied, proceed and connect a flat Iron and test for at least 20 minutes.
• Projects described in here involve lethal voltages that can end your life or cause damage to property in an instant. do not attempt any of the projects unless you have sufficient knowledge and expertise as far as electricity and safety are concerned.
• The author will not assume any responsibility for equipment failures, damages to property or life caused by any or part of the projects listed here within.