Page 3 of 5 FirstFirst 12345 LastLast
  1. #21
    Have a read throught this http://www.mycncuk.com/threads/9268-...se-Spindle-VFD. Message #46 gives a good diagram for all the electrics and shows where to put fuses or MCB's. One nice thing about the UK is we have fuses in our mains plugs, so if something goes wrong there is generally a fuse that will blow before any major damage is caused.
    Because you are using a torroidal transformer, the inrush current (how much current is taken when you first apply mains power) can be many times the rated current of your transformer. You may have to use a bigger fuse than you think, but also be carefull to not go too far as you could cause damage if you do get a short.
    Can I also make a suggestion to you. The wires from the transformer to the rectifier and to the capacitors should be much shorter and more heavy duty - at least the same wire size as the transformer wires.

  2. #22
    Quote Originally Posted by Graeme View Post
    Have a read throught this http://www.mycncuk.com/threads/9268-...se-Spindle-VFD. Message #46 gives a good diagram for all the electrics and shows where to put fuses or MCB's. One nice thing about the UK is we have fuses in our mains plugs, so if something goes wrong there is generally a fuse that will blow before any major damage is caused.
    Because you are using a torroidal transformer, the inrush current (how much current is taken when you first apply mains power) can be many times the rated current of your transformer. You may have to use a bigger fuse than you think, but also be carefull to not go too far as you could cause damage if you do get a short.
    Can I also make a suggestion to you. The wires from the transformer to the rectifier and to the capacitors should be much shorter and more heavy duty - at least the same wire size as the transformer wires.
    Thank you very much for the link and for the suggestion. I will unsolder everything and switch to bigger wires. I was using typical 230V wires and did notice that they were a bit thin but they are the same size as the input 230V on the transformer. I'll do that again next week and post back here.

  3. #23
    For info here was my power supply build. Bit late now (!) but you can see the colour coding on the transformer, plus I also noted higher gauge wires on the secondary which I matched. Remembering back to my school days when the transformer coil drops the voltage it increases the current, which means larger cables. So I think that on the primary you have high voltage and low current (small gauge) and on the secondary you have low voltage and high current (large gauge).

    http://www.mycncuk.com/threads/6988-routercnc_MK3/page5

    Post #43 onwards
    Last edited by routercnc; 13-12-2015 at 08:12 PM.
    Building a CNC machine to make a better one since 2010 . . .
    MK1 (1st photo), MK2, MK3, MK4

  4. #24
    Hello routercnc, thank you very much for the link ! I have one question though: when looking at your diagram, I see that while wiring both yellow and black together you also wired them to the star point. Is that correct ?
    On Wednesday I will go get the fuses I need. I will solder the capacitors and crimp terminals with bigger wires. The nice thing about the set I have is that I am using an old PSU box from a PC and it fits perfectly inside a desktop PC box. Plus it has the integrated switch, and a good start for a star point.

    I'll keep you guys updated. Also think it's time to start my build thread.

  5. #25
    Which post did you see those wires connected to Earth? Can't find which one you mean
    Building a CNC machine to make a better one since 2010 . . .
    MK1 (1st photo), MK2, MK3, MK4

  6. #26
    Quote Originally Posted by routercnc View Post
    Which post did you see those wires connected to Earth? Can't find which one you mean
    Post #43, image #3, the yellow an black are drawn in front of AC2 and AC3, which go straight to GND..Click image for larger version. 

Name:	linear_supply_wiring.JPG 
Views:	92 
Size:	98.1 KB 
ID:	16803

  7. #27
    Clive S's Avatar
    Lives in Marple   Stockport, United Kingdom. Last Activity: 14 Hours Ago Forum Superstar, has done so much to help others, they deserve a medal. Has been a member for 5-6 years. Has a total post count of 2,309. Received thanks 403 times, giving thanks to others 35 times. Made a monetary donation to the upkeep of the community. Is a beta tester for Machinists Network features.
    NO none of the wires from the transformer connect to a star point that is only for all the earths. Also do not connect an earth to the bolt that holds down the transformer unless you do it at the bottom and not at the top like this pic showsClick image for larger version. 

Name:	IMG_1588.jpg 
Views:	79 
Size:	462.9 KB 
ID:	16802 as it creates a shorted turn around the transformer. I hope the guy that built this doesn't mind me using it to show the problem.
    Last edited by Clive S; 13-12-2015 at 11:47 PM.
    ..Clive
    The more you know, The better you know, How little you know

  8. #28
    I see :) Thanks for the advice :) Jazz had noted that before as well :) Sounds like this guy's control box will blow up some time hu :s
    It's funny because I had seen this image before on Google and always thought the setup looked quite nice :)

  9. #29
    Oops! Wrong again
    Last edited by Robin Hewitt; 14-12-2015 at 11:55 AM.

  10. #30
    Quote Originally Posted by Robin Hewitt View Post
    Oops! Wrong again
    ?

Page 3 of 5 FirstFirst 12345 LastLast

Similar Threads

  1. Toroidal Transformer
    By Carlb1058 in forum General Electronics
    Replies: 7
    Last Post: 17-08-2013, 06:54 AM
  2. FOR SALE: 2x55V Torroid Transformer
    By m_c in forum Items For Sale
    Replies: 4
    Last Post: 02-05-2013, 11:57 AM
  3. Centre tap transformer?
    By veedub1955 in forum General Electronics
    Replies: 5
    Last Post: 15-05-2012, 11:10 PM
  4. FOR SALE: Transformer - large toroidial from amplifier
    By Jonathan in forum Items For Sale
    Replies: 1
    Last Post: 05-06-2011, 05:31 PM
  5. Solid State Relay to Switch Transformer?
    By m_c in forum General Electronics
    Replies: 13
    Last Post: 08-09-2008, 11:19 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •