Trying to find a greater than 240v ac source on 150w 12v dc to 240v ac car inverter

[UNiT5]

I own a small "200w" 12v dc to 240v ac inverter i bought to power a lighting ballast.
The ballast actually needs between 330v ac to 400 ac to turn on.
This inverter i found out actually produces around 330v ac but is then stepped down to 220 - 240v ac.
I managed to jump the 330v source and ran the 330v source out to my lighting ballast.
Here is a picture of that inverter







It was working fine a few years back but bringing it out of its hibernation i've tried to power the lighting ballast only to find the ballast making a weird buzzing sound.
After testing the output voltage of the jumped transistor, it was reading 280v which is about 50v shy of what the ballast needs.
I then went to my local electronics store and picked up a new 150w inverter which is much larger then the older one i have.
After pulling the guts out of that one thinking that the schematics would be the same, i'm having a hard time trying to work out finding a voltage source on this board 330v or greater.
I've tried pronging around with my multimeter to no avail.
Am wondering if it would be possible on such board.
Here is some pics of the new inverter









Kind regards

 

[BradtheRad]

In case this could be a solution...

AC in AC out semi-doubler, made from diode-capacitor networks. Caps charge in series, discharge in parallel.



By choosing the right Farad value you add 100V or more to incoming mains AC (while preserving sine shape).

The transistors turn on positive polarity, then negative polarity. Their purpose is not necessarily to drop voltage.

 

[UNiT5]

In case this could be a solution...

AC in AC out semi-doubler, made from diode-capacitor networks. Caps charge in series, discharge in parallel.

View attachment 159305

By choosing the right Farad value you add 100V or more to incoming mains AC (while preserving sine shape).

The transistors turn on positive polarity, then negative polarity. Their purpose is not necessarily to drop voltage.

Thank you. So in your wisdom with the new inverter would I be able to find a 100+ Ac voltage source on the neutral side circuit, preferably on the out side of a capacitor? and connect to the ac live circuit essentially adding more voltage to the already 240v? Are you able to point me in the right direction as to where I would have to solder a line to the ac output? Cheers

 

[UNiT5]

Would I be able to combine let’s say a 100+v source from the old inverter and connect it parallel to the new inverter essentially giving me 350 odd volts. Would this be safer? I would prefer using only one inverter if possible to do the job.

 

[BradtheRad]

There is no need to open up your inverter. My semi-doubler hooks up the left terminal to one live AC wire.
The ground icons to the other live AC wire.

The load is your ballast. Attach one end to the join between the NPN & PNP.

The capacitors need a voltage rating which can tolerate the maximum they can be exposed to.
They need to tolerate the maximum current.
They can be electrolytic because each charges to either positive or negative. Electrolytics must be oriented properly because reverse polarity destroys them.

For the load I made it 100W (a large share of your inverter rating). However I don't know about your ballast. Perhaps it runs at 20W? 50W? Perhaps you can reduce capacitor values and bias current accordingly.

Note: My design is not the same as a voltage doubler. It was not tested at high power levels. If your ballast requires greater voltage then you may need to step up to a normal voltage doubler, in combination with the transistors.

 

[UNiT5]

There is no need to open up your inverter. My semi-doubler hooks up the left terminal to one live AC wire.
The ground icons to the other live AC wire.

The load is your ballast. Attach one end to the join between the NPN & PNP.

The capacitors need a voltage rating which can tolerate the maximum they can be exposed to.
They need to tolerate the maximum current.
They can be electrolytic because each charges to either positive or negative. Electrolytics must be oriented properly because reverse polarity destroys them.

For the load I made it 100W (a large share of your inverter rating). However I don't know about your ballast. Perhaps it runs at 20W? 50W? Perhaps you can reduce capacitor values and bias current accordingly.

Note: My design is not the same as a voltage doubler. It was not tested at high power levels. If your ballast requires greater voltage then you may need to step up to a normal voltage doubler, in combination with the transistors.

Please forgive me your first post went straight over the top of my head. Now I understand. The circuit you posted can be made using a home made pcb/breadboard? and store bought components and will help by adding an extra 100v or greater from my already 240v ac source coming from my inverter! Cool!
Now the tricky part, its been a looooong time since ive mucked around with home made pcbs / electronics! And considering i need to get my ballast running before the end of the month will be a bit of a hassle for me! Much appreciate you help sp far.
What would be your suggestion in producing such a circuit as quickly as possible?
Would you do breadboard?

 

[Easy peasy]

inverter + 200W auto transformer to get your 350Vac ...

 

[BradtheRad]

Would you do breadboard?

A breadboard has thin metal springy contacts, suited for 22 gauge wire and current up to maybe 1 Ampere. It's common to test a low power circuit on breadboard, then build a robust version on perfboard. Leave room to make modifications.

A ballast (as I understand it) draws higher current at startup to get the lamp lit. Then it allows current to drop to normal running level. It's a good idea to learn what current levels go through your system. You can decide whether to use diodes rated 1 Amp (say cheap 1N4007) or 3 Amps.

The 20uF capacitors might have several Amperes going through them. That's a lot for small components. You might rather gang several caps in parallel.

The bias resistors need to be several Watts even though they're tens of kOhms.

 

[UNiT5]

inverter + 200W auto transformer to get your 350Vac ...

May you please elaborate? I tried searching google to no avail. Please note, i'm no electrical engineer and need simpleton terms for better understanding, cheers.

- - - Updated - - -

A breadboard has thin metal springy contacts, suited for 22 gauge wire and current up to maybe 1 Ampere. It's common to test a low power circuit on breadboard, then build a robust version on perfboard. Leave room to make modifications.

A ballast (as I understand it) draws higher current at startup to get the lamp lit. Then it allows current to drop to normal running level. It's a good idea to learn what current levels go through your system. You can decide whether to use diodes rated 1 Amp (say cheap 1N4007) or 3 Amps.

The 20uF capacitors might have several Amperes going through them. That's a lot for small components. You might rather gang several caps in parallel.

The bias resistors need to be several Watts even though they're tens of kOhms.

The circuit seems simple enough im sure, however not coming from an electronic engineering background i may need some help building it...

 

[Easy peasy]

an auto transformer is a non isolated transformer that can take in 230Vac on a tapping and output 350Vac, because it is not isolated if uses far less wire than a standard isolating transformer ( and a smaller lamination size ) and is therefore quite small for its power rating - usually half in comparison - you may have to get one specially wound at your nearest transformer winder - although the cost for a 100VA sized auto-transformer should be very moderate.

 

[UNiT5]

an auto transformer is a non isolated transformer that can take in 230Vac on a tapping and output 350Vac, because it is not isolated if uses far less wire than a standard isolating transformer ( and a smaller lamination size ) and is therefore quite small for its power rating - usually half in comparison - you may have to get one specially wound at your nearest transformer winder - although the cost for a 100VA sized auto-transformer should be very moderate.

Very much appreciated, spoke to a firm in Sydney, they've quoted for a 200va rated 240vac - 380vac autotransformer made to order. Should i just stick to 100va as you advised?

 

[Easy peasy]

100 VA is 263mA on the 380V tapping if this is enough then yes, if you need more then ask for more

you have a 200W inverter, so 200VA would be a match to that ( 230V, 870mA in, 380V, 526mA out ) ...