Aaron's Homepage Forum
Aaron's Homepage Forum
Home | Profile | Register | Active Topics | Members | Search | FAQ
Username:
Password:
Save Password
Forgot your Password?

 All Forums
 Electronics
 Power Supply
 12/120V inverter again
 New Topic  Reply to Topic
 Printer Friendly
Previous Page | Next Page
Author Previous Topic Topic Next Topic
Page: of 63

audioguru
Nobel Prize Winner

Canada
4214 Posts

Posted - May 12 2008 :  10:42:29 AM  Show Profile  Reply with Quote
Here we go again:
1) The max current from the opamps is only 20mA so the max input to each 2SD880 transistor is only 20mA and its max output current might be 300mA.
2) The max input to the 2N3055 transistor is 300mA and its max output might be 4.5A.
3) The max input to the BUT100 is 4.5A and its output might be 45A.

The peak output current is 49.8A so the RMS output current is 35.2A.
The peak output voltage is 8.2V so the RMS voltage is 5.8V. The transformer should be 6V-0V-6V for the output voltage to be correct.
The power into the transformer is 35.2A x 5.8V= 204W RMS. If the transistors have low gain then the output power and output voltage is less.
The transistors have a power loss which makes 95W of heat.
The average current from the battery is 24.9A.

If you use a pair of modern Mosfets then the power to the transformer will be about 400W and the voltage will be correct. 2 pairs of Mosfets make 800W.

The LM10 circuit has a low logic output when the battery voltage is low. It is designed to give a low logic input to a NAND gate. It must be re-designed to give a high logic input to a NOR gate. Or you can use the spare 3rd gate in the CD4025 to invert the output from the LM10.

The input current of CD4xxx Cmos gates is ZERO.
Go to Top of Page

audioguru
Nobel Prize Winner

Canada
4214 Posts

Posted - May 13 2008 :  12:20:33 AM  Show Profile  Reply with Quote
quote:
Originally posted by JUAN DELA CRUZ
Can I use "2 Pair of IRFZ44 Mosfet" to obtain "800W" output..????
..........so if I'll use "3 pair of IRFZ44 Mosfet the output power will be "1200W"..?????
I think so but I have never tried to blow up a car battery with that much current.

How about this circuit( w/ LM741)???
It will do the same as the LM10 circuit.

quote:
Can this circuit can supply "High" current to turn-off ......"TWO NOR GATE of CD4025"????

Its output voltage is low not high. It needs to use the 3rd unused gate in the CD4025 as an inverter to feed a logic high voltage to the CD4025 gates so they can turn off the Mosfets.

quote:
Can I connect it directly to series resistor & Zener voltage spike filter???

I think so.

[quote]What is the purpose of "100K Pot."????.....What type???
...like the Pot. used in a Audio Amp.?????
.... How many Wattage is needed???


It adjusts the voltage for the low voltage cutoff to work. It is not a logarithmic volume control, it is a linear pot. Calculate the tiny amount of power it dissipates.
Go to Top of Page

audioguru
Nobel Prize Winner

Canada
4214 Posts

Posted - May 13 2008 :  10:22:56 AM  Show Profile  Reply with Quote
A zener diode limits a voltage spike. A 15V regulator does not work when its input is less than 18V and a voltage spike goes through it because it reacts too slowly.

You found a very old circuit. I think the 1k resistors in series with the gates of the Mosfets should be 47 ohms. The resistors have an extremely low current in them so 1/4W is fine.

I think a transformer from a microwave oven is cheap. It is designed for full power for a short time so it wastes a lot of power if it is not at full power. It might overheat and its output voltage might have poor voltage regulation.
The transformer should be 8V-0-8V. With an 800W load the average current from the battery is about 75A. A huge car battery will last for about half an hour if it doesn't boil dry sooner.
Go to Top of Page

audioguru
Nobel Prize Winner

Canada
4214 Posts

Posted - May 13 2008 :  10:03:11 PM  Show Profile  Reply with Quote
The capacitor in the snubber is certainly not 220uF. It is 220nF which is 1000 times smaller.
The values of the snubber and where they are placed depends on how the transformer makes voltage spikes. Each make of transformer is different.
Go to Top of Page

audioguru
Nobel Prize Winner

Canada
4214 Posts

Posted - May 14 2008 :  3:03:53 PM  Show Profile  Reply with Quote
Most of your schematics have disappeared so I don't know what you are doing amymore.

Now you have inverted the input to the flip-plop latch so it won't work. You need to invert its output instead.
I always inhibit unused inputs by connecting them to the positive supplu or to ground like this:

Download Attachment: low battery cutoff again and again.PNG
14.48 KB

Go to Top of Page

audioguru
Nobel Prize Winner

Canada
4214 Posts

Posted - May 15 2008 :  10:01:58 AM  Show Profile  Reply with Quote
I have never seen a transformer for a microwave oven that is made in your country.

The LM10 circuit works the same as the 741 circuit.

The reset pushbutton is normally open.
Go to Top of Page

senahia
New Member

Ghana
2 Posts

Posted - May 16 2008 :  08:54:41 AM  Show Profile  Reply with Quote
sir i will be happy if you can send me schmatic diagram of 12vdc to 240vac, and it will supplyed by solar panel of 12vdc and lead acid battery of 12vdc please i need immediate diagram for my projrct work(i need sine wave inverter diagram)
Go to Top of Page

audioguru
Nobel Prize Winner

Canada
4214 Posts

Posted - May 16 2008 :  1:05:52 PM  Show Profile  Reply with Quote
quote:
Originally posted by JUAN DELA CRUZ
Regarding about the Xformer....If I'll make a 8v -0v- 8v primary winding(w/ 220V secondary) I'll turn the magnetic wire "8 times" in the iron core????

The turns ratio of the primary to the secondary determines the voltage. It probably will not be 8 times.

quote:
Do you have an short & overvoltage protection circuit that I can use w/ my Modified Sine Inverter to protect the Load...cause I'll using it to power a modified sine compatible COMPUTER.????

We talked about an over-voltage circuit in these forums recently. It was a window caomparator to turn off the Mosfets if the battery voltage is too high or too low.
You need to design a simple over-current detector circuit yourself.

quote:
What will be the value of ZENER diode to Protect the Power mosfet from "Voltage Spike" when the Battery clip is suddenly disconnected????[/b]

I don't know. Maybe a 16V/1W zener diode will work.
Go to Top of Page

audioguru
Nobel Prize Winner

Canada
4214 Posts

Posted - May 17 2008 :  11:13:39 AM  Show Profile  Reply with Quote
You found a very old under-voltage and over-voltage circuit. A simpler modern circuit is made with two opamps or comparators performing as a window comparator. Dennis recently posted the schematic for his window comparator.

What will cause the 12V input voltage of your inverter to be too high?
Go to Top of Page

kivdenn
Nobel Prize Winner

Uganda
535 Posts

Posted - May 17 2008 :  11:39:00 AM  Show Profile  Reply with Quote
Please can any one help me change this charger circuit http://www.aaroncake.net/circuits/charger2.asp to a 24V and also 48V charger circuit. Show me how to change the necessary parts especialy resistor values. Thanks
Dennis
Go to Top of Page

JUAN DELA CRUZ
Mad Scientist

Philippines
476 Posts

Posted - May 18 2008 :  12:25:48 AM  Show Profile  Reply with Quote
quote:
Originally posted by audioguru

You found a very old under-voltage and over-voltage circuit. A simpler modern circuit is made with two opamps or comparators performing as a window comparator. Dennis recently posted the schematic for his window comparator.

What will cause the 12V input voltage of your inverter to be too high?



Thank you again Mr. audioguru,

The 12V input voltage of my modified sine inverter is O.K.

........but my problem lies at the output of the Xformer(secondary side).The voltage in the output of my inverter varies.
(due to battery voltage variation, i.e. approx. 13.8V when full & 9V
when nearly discharge).

....do you think a Zener diode can regulate the output before coming to the primary side of the Xformer????

...the down side will be less power output because less RMS voltage will go to the primary winding right...???

.......but the output will be more stable.


OR....do think an "automatic voltage control" w/ SCR will be the answer????
quote:




P.S...........Do you think this charger(Aaron designed) can lenghten the charge of the battery of my Modified sine inverter if I'll power it in the output of my inverter & then automatically charge the battery (i.e. disconnect when fully charge & then charge it again when the charge is low)??????
Download Attachment: charger2-1.gif
4.32 KB






Thank you.....


juan dela cruz
Penniless INVENTOR

Edited by - JUAN DELA CRUZ on May 18 2008 01:47:24 AM
Go to Top of Page

audioguru
Nobel Prize Winner

Canada
4214 Posts

Posted - May 18 2008 :  10:56:57 AM  Show Profile  Reply with Quote
You should not regulate the output voltage of your simple inverter by using a huge zener diode to short its input with about 700W of wasted power. The inverter circuit is too simple for voltage regulation.

The inverter cannot charge itself because that is impossible perpetual motion. The input power to a charger is more than its output power so power is wasted and the battery will run down instead of charging.
The charger must be powered from the mains.
Go to Top of Page

JUAN DELA CRUZ
Mad Scientist

Philippines
476 Posts

Posted - May 19 2008 :  12:15:31 AM  Show Profile  Reply with Quote
quote:
Originally posted by audioguru

You should not regulate the output voltage of your simple inverter by using a huge zener diode to short its input with about 700W of wasted power. The inverter circuit is too simple for voltage regulation. [quote]


Thank you Mr. Audioguru....

What should I do so that the output voltage of my modified sine inverter will be more stable.

...you said that using a Zener to regulate the output will wasted a lot of power.

...what if the output of the individual power mosfet is regulated so that the voltage coming to the primary winding of the xformer is stable likewise the output will be stable right???


Thank you.

juan dela cruz
Penniless INVENTOR

Edited by - JUAN DELA CRUZ on May 19 2008 12:16:18 AM
Go to Top of Page

audioguru
Nobel Prize Winner

Canada
4214 Posts

Posted - May 19 2008 :  12:45:15 AM  Show Profile  Reply with Quote
If you adjust the input to the Mosfets so that they regulate the voltage to the transformer then the Mosfets will melt.
If the Mosfets must reduce the voltage by 2V then at 80A their power wasted is 160W in addition to their power loss.

Modern inverters use Pulse-Width-Modulation to have a regulated average current in the load. The Mosfets turn on completely and turn off completely to stay fairly cool.
Your simple inverter is not designed for Pulse-Width-Modulation. It is old and CHEAP!
Go to Top of Page

kivdenn
Nobel Prize Winner

Uganda
535 Posts

Posted - May 19 2008 :  02:46:59 AM  Show Profile  Reply with Quote
quote:
Originally posted by JUAN DELA CRUZ

quote:
Originally posted by audioguru

You found a very old under-voltage and over-voltage circuit. A simpler modern circuit is made with two opamps or comparators performing as a window comparator. Dennis recently posted the schematic for his window comparator.

What will cause the 12V input voltage of your inverter to be too high?



Thank you again Mr. audioguru,

The 12V input voltage of my modified sine inverter is O.K.

........but my problem lies at the output of the Xformer(secondary side).The voltage in the output of my inverter varies.
(due to battery voltage variation, i.e. approx. 13.8V when full & 9V
when nearly discharge).

....do you think a Zener diode can regulate the output before coming to the primary side of the Xformer????

...the down side will be less power output because less RMS voltage will go to the primary winding right...???

.......but the output will be more stable.


OR....do think an "automatic voltage control" w/ SCR will be the answer????
quote:




P.S...........Do you think this charger(Aaron designed) can lenghten the charge of the battery of my Modified sine inverter if I'll power it in the output of my inverter & then automatically charge the battery (i.e. disconnect when fully charge & then charge it again when the charge is low)??????
Download Attachment: charger2-1.gif
4.32 KB






Thank you.....




Hey all,
I would like to modify this circuit to a 24V battery charger circuit. How do i do that I mean what parts should I change to what?.Thanks
Dennis
Go to Top of Page
Page: of 63 Previous Topic Topic Next Topic  
Previous Page | Next Page
 New Topic  Reply to Topic
 Printer Friendly
Jump To:
Aaron's Homepage Forum © 1995-2020 AARONCAKE.NET Go To Top Of Page
This page was generated in 0.17 seconds. Snitz Forums 2000