redesign or conversion of dc to ac circuit

Discussion in 'Homework Help' started by maximuz, Sep 18, 2015.

  1. maximuz

    Thread Starter New Member

    Sep 15, 2015
    Hello everyone, I'm just wondering if anyone can help me to redesign or convert the circuit from dc to ac. This is for my electrical subject I'm still in a point of adjustment in learning everything, btw I'm a mechanical engineering student. I've attached the file for the circuit for illustration and below is the description required to do the task.

    Redesign the circuit due to the power supply changes from direct current “DC” to alternating current “AC”. The new main power supply to the system circuit is 230 VAC. It is connected to the existing circuit (two 24 VDC motors and two lamps or LEDs – Red and Green). Additional components are required but are not limited to in your new system such as a step-down transformer, a full-wave rectifier (AC-DC supply), resistors, capacitors, emergency power supply, etc.

    draw a new circuit diagram and write a report of your new proposed system which must satisfy the following criteria:
    - Electrical supply (AC, DC, power, frequency, current rating and power factor).
    - Machines’ and components’ specifications include electrical and power factor calculation.
    - Type of controls (switches, sensors, etc.) for isolation, shutdown and emergency.

    * Another thing is there any tips or good resources (aside from this website) such as books, websites, etc. that I can visit/read to complete this task, honestly I don't have any idea where to start.

    * Is there any free simulation program that you can suggest where I can create a circuit diagram and test it, and print the diagram as well.

    I really appreciate any help.

  2. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    Many members here use LTspice, a free download from Linear Technology, for schematic drawing and simulation. The Yahoo LTspice User group can offer help and has freely downloadable libraries of third-party spice models to supplement those in the standard LTS download.
  3. maximuz

    Thread Starter New Member

    Sep 15, 2015

    thanks so much for this. I really appreciate it.
  4. WBahn


    Mar 31, 2012
    With those resistors in series with your motors and the LEDs, your motors are limited to drawing about one milliamp. The relay coil probably draws more than that.

    You say these are 24 VDC motors but your circuit has then being powered by a 12 V battery.

    If your additional components are not limited -- especially if it can include an "emergency power supply" -- then just specify using a commercial power supply that can run from 230 VAC and can output the voltage and current you need. My guess is that such an approach is not what is being looked for, but you haven't given design constraints that would preclude it.
  5. Russmax


    Sep 3, 2015
    I read maximuz post and thought, doesn't everyone know how to put together a transformer, some diodes and a cap to make a DC power supply? I think that because 40 years ago, when I was 12, I bought a Forrest M. Mims' electronics book, which taught me how to make an AC-DC converter. You may not be a kid any more, and Radio Shack stopped selling them long ago, but you can still have a copy: I think Vol IV will have a basic converter, but the others may also.

    OK, that would have helped you as a kid, putting you on the path of light as an electrical engineer, instead of the dark path of mechanical engineering, but what you need is help right now. AAC is an awesome place, and it has just what you need, which is a quick set of worksheets on designing power supplies with transformers, diodes, and stuff. I cannot fathom why you said "aside from this website", unless you've already studied all the circuits at this link, and want more:

    OK, you want more. How about these links. They cover some basics and some specifics: Supply

    You may need to go to the library and look at textbooks on the topic.