A little electrical help

Discussion in 'General Discussions and Advice' started by shane, 8 Feb 2010.

  1. shane

    shane

    Joined:
    1 Jun 2007
    Posts:
    668
    Likes Received:
    0
    Location:
    durban
    Hi Guys,
    I am in need of some advise or help from anyone with some electrical back round.
    The pump I have in mind to use is rated at 200 watts.
    Now for my question.
    Firstly power is fed from a 2 channel timer, the 1 channel is fed directly to the pump. The second channel goes through a speed controller ( was thinking about using a fan speed controller ). Basicly I wanted the pump to run flat out during the " daylight " hours on 1 channel but then at " night " swop over to the other channel and run at a reduced flow for the night.
    If the electrical demand or draw is less than what the fan controller is rated for then would this type of setup work?
    Please offer any comments.
    Cheers
     
  2. AdS Guest




    to hide all adverts.
  3. dallasg

    dallasg Moderator MASA Contributor

    Joined:
    14 Dec 2008
    Posts:
    16,769
    Likes Received:
    582
    Location:
    Sandton
    hi shane, first the pump needs to be able to run at lower or variable power, but if its less it should be fine.
    lighty will have a good answer, he is an electrical genius
     
  4. neo

    neo

    Joined:
    25 Jun 2009
    Posts:
    582
    Likes Received:
    2
    Location:
    Centurion
    By the sound of it your speed controller is going to reduce the supply voltage to the pump and i dont know if the pump is designed to operate like this.
     
  5. shane

    shane Thread Starter

    Joined:
    1 Jun 2007
    Posts:
    668
    Likes Received:
    0
    Location:
    durban
    I was hoping that be reducing the supply voltage that the pump would slow down.
    Cheers
     
  6. Yuri

    Yuri

    Joined:
    9 Jul 2008
    Posts:
    1,999
    Likes Received:
    22
    Location:
    Centurion
    are you talking about a desk fan
    there is no speed controller on a desk fan it is a multi speed motor
    the only why to get the speed down on am motor is to lower the hertz (Hz)
     
  7. Yuri

    Yuri

    Joined:
    9 Jul 2008
    Posts:
    1,999
    Likes Received:
    22
    Location:
    Centurion
    i forgot to
    the why to do this is to get a ( variable speed motor drive)
     
  8. shane

    shane Thread Starter

    Joined:
    1 Jun 2007
    Posts:
    668
    Likes Received:
    0
    Location:
    durban
    The speed controller I was talking about was from one of those 3 bladed steel ceiling fans ( sort of industrial type) not the normal wooden look a like ceiling fans.
    Cheers
     
  9. Yuri

    Yuri

    Joined:
    9 Jul 2008
    Posts:
    1,999
    Likes Received:
    22
    Location:
    Centurion
    it will not work
    thy are multi speed motors
     
  10. Reef Maniac

    Reef Maniac MASA Contributor

    Joined:
    15 May 2007
    Posts:
    2,899
    Likes Received:
    112
    Location:
    Bloemfontein
    Why do you want to do that - waves don't slow down at night :whistling: :whistling:

    Depending on the type of motor, this will probably not work. Is this an external electrical motor turning a separate (mag-drive) pump? If so, keep in mind that the motor normally has a cooling fan built into it, and running the motor slower might cause it to over-heat.

    You could build a zero-crossing SCR-controlled "burst fire" mains controller - these are pretty easy to DIY if you have a bit of electronics know-how (Google it...)

    Hennie
     
  11. shane

    shane Thread Starter

    Joined:
    1 Jun 2007
    Posts:
    668
    Likes Received:
    0
    Location:
    durban
    Thanks Hennie,
    The motor in question is a submersible pump, Resun PG 18 000.
    I did not want to totally stop the pump but to rather slow it down, smaller water movement at night.
    Cheers
     
  12. lIghty

    lIghty

    Joined:
    3 Nov 2007
    Posts:
    5,053
    Likes Received:
    52
    Location:
    Westville, Durban
    Thanks Dallas

    Like Hennie said, it probably won't work, especially if its a simple submersible pump!

    Please note, I'm not a expert on AC motor control, but generally speed control is done via a phase controlling and not voltage control, which is a bit trick, but can be done if you know electronics. I must add, even with these devices, not all pumps can be controlled.
     
  13. lIghty

    lIghty

    Joined:
    3 Nov 2007
    Posts:
    5,053
    Likes Received:
    52
    Location:
    Westville, Durban

    Could you not run 2 serperate pumps, switching between the 2?
     
  14. Yuri

    Yuri

    Joined:
    9 Jul 2008
    Posts:
    1,999
    Likes Received:
    22
    Location:
    Centurion
    that is a good idea much cheaper

    ac induction motors speed are dependent on the amount of pole pears
    the more poles it has the slower the motor are (have to rewind the motor) to make it faster or slower
    the other thing to make it slower is to make the Hz less
    we have 50Hz in South Africa that is a constend and never changes
    so the stater speed will not go faster than 3000rpm with slip that makes the rotor speed just slower
    in the USA thy can run motors faster thy have 60Hz
     
  15. Reef Maniac

    Reef Maniac MASA Contributor

    Joined:
    15 May 2007
    Posts:
    2,899
    Likes Received:
    112
    Location:
    Bloemfontein
    Yes, I understand what you want to do... the question is: "but why ???"

    Hennie
     
  16. shane

    shane Thread Starter

    Joined:
    1 Jun 2007
    Posts:
    668
    Likes Received:
    0
    Location:
    durban
    Thanks for all the info guys, it seems that I idea would have not worked.
    Hennie, so what you are saying is that I should run the pump non stop?
    If I went ahead and installed this pump and started to run it , do you think that the fish would be stressed out as they are not acustom to so much water movement.
    Cheers
     
  17. Reef Maniac

    Reef Maniac MASA Contributor

    Joined:
    15 May 2007
    Posts:
    2,899
    Likes Received:
    112
    Location:
    Bloemfontein
    I think they will enjoy it :biggrin:

    You obviously don't want a direct "blast" onto any coral, or close to your sand, but strong water movement is natural for the fish, as long as there are some "sheltered" areas where they can "hide" at night (i.e. cracks/"fissures" or other small open areas between your live rock).

    My 1.8m tank has close on 50 000 liters per hour flow, and that's still pretty light...
    Check out the two short video clips in this thread: Chaotic water movement - Marine Aquariums of South Africa

    Hennie
     
Recent Posts

Loading...
Similar Threads - little electrical help Forum Date
Is this little guy good or bad? General Discussions and Advice 29 Sep 2016
My Little Black Box Medium Tanks 28 Jun 2016
Little White Spots on Back Overflow General Discussions and Advice 4 Apr 2016
My little secret Medium Tanks 12 Mar 2016
My little 4ft reef Medium Tanks 9 Mar 2016
Little White Things? ID Needed 7 Jan 2016
Admiral Bous's little kitchen tank Medium Tanks 21 Dec 2015