500W Inverter Circuit Diagram

Discussion in 'General Electronics Chat' started by Omoshie, Mar 5, 2008.

  1. Omoshie

    Omoshie Thread Starter New Member

    Joined:
    Mar 5, 2008
    Messages:
    1
    Pls i need inverter circuit diagram for about 500W
  2. beenthere

    beenthere AAC Fanatic!

    Joined:
    Apr 20, 2004
    Messages:
    15,815
    Location:
    Missouri, USA (GMT -6)
  3. Audioguru

    Audioguru New Member

    Joined:
    Dec 20, 2007
    Messages:
    9,411
    Location:
    Ontario, Canada
    Harry's inverter circuit has the multivibrator transistors operating from 12V.
    Their emitter-base junctions break down in an avalanche breakdown when the multivibrator's supply voltage is more than about 7V. It is bad for them.

    The output of his inverter is a square-wave but many electronic products need the higher peak voltage of a sine-wave or of a modified sine-wave.
  4. thingmaker3

    thingmaker3 Moderator Staff Member

    Joined:
    May 16, 2005
    Messages:
    5,072
    Location:
    Rural, Oregon GMT -8
    Don't the base resistors drop most of that 12V?

    Indeed. This is especially true of induction motors. I remember trying to run a drill motor from an inverter back in the early 80's. I got a whole 1/8 turn from it.
  5. S_lannan

    S_lannan Active Member

    Joined:
    Jun 20, 2007
    Messages:
    247
    Location:
    Australia
    i was looking up 3phase inverters and saw a 500watt 3 phase for electric motors that used 60hz square waves to drive a motor.

    would that inverter work well for a motor? i'm curious.
  6. thingmaker3

    thingmaker3 Moderator Staff Member

    Joined:
    May 16, 2005
    Messages:
    5,072
    Location:
    Rural, Oregon GMT -8
  7. Audioguru

    Audioguru New Member

    Joined:
    Dec 20, 2007
    Messages:
    9,411
    Location:
    Ontario, Canada
    No.
    The capacitor charges to 11.3V. Then the other transistor conducts and tries to force this transistor's base down to -11.1V but the emitter-base junction breaks down at about -7V.
  8. thingmaker3

    thingmaker3 Moderator Staff Member

    Joined:
    May 16, 2005
    Messages:
    5,072
    Location:
    Rural, Oregon GMT -8
  9. foggysail

    foggysail New Member

    Joined:
    Aug 5, 2009
    Messages:
    1
    Yeah, I know this is an old thread but thought I would comment on the design.

    First, Harry is using a toroidal style power transformer. Normally this style is fine except for the difficulty in manufacturing. But there is one other problem in push/pull inverter circuits.

    If the timing sequences between the two switches differs by anything, and I do mean anything, over a period of cycles the operating point on the BH curve will walk up the curve or down the curve. It acts like a DC component. The result of curve walking is the transformer can/WILL saturate even if for olny a few cycles.

    The result can be disastrous for the switches!!!

    Yes, people do design things that get into production with similar problems and then one wonders why "gee, what caused that switch to fail!" Gapping the core can help. Gapping the core does not stop the problem but it greatly reduces it by "tilting" the BH curve. It also add to the magnetizing current which adds to the switch current along with other things and must be addressed during the design.

    One of the worse situation I came across when I was a design engineer was so called simple circuits that popped up during engineering concept meetings along with the challenge "why won't this circuit work?" Many of those simple circuits did indeed work but it took many hours of engineering to establish the working boundary conditions to ensure it worked over the limits of component, voltage, current and temperature tolerances.

    Foggy
Similar Threads: 500W Inverter
Forum Title Date
General Electronics Chat 500w Mosfet inverter Circuit Oct 29, 2012
General Electronics Chat Need help on 24V DC input to 240VAC, 500W inverter circuit design Nov 14, 2009
General Electronics Chat 500w 2v psu Mar 23, 2014
General Electronics Chat Inverter not working Aug 25, 2014
General Electronics Chat 5-Phase Inverter or VFD Aug 16, 2014

Share This Page