Page 1 of 2 1 2 LastLast
Results 1 to 10 of 11

Thread: Design for DIY Fan Speed Controller

  1. #1

    Join Date
    Nov 2017
    Location
    De Pijp
    Posts
    10,915
    Thanks
    28,179
    Been Thanked: 46,725 Times

    Default Design for DIY Fan Speed Controller

    Ive got quite a few transformers and switches lying in the parts bin so it occurred to me I might as well go and build a switched fan controller.

    For the design I need some information from fellow growers based roughly on their minimum fan speeds in terms of %

    Do we know what voltage the fan is running at when on the minimum speed? This will help my choose the right secondary voltage

    Has anyone measured the power at this minimum speed to see what the effect is on current draw?

    Theory says that if you half the speed, you will reduce the power 8 times

    Cheers
    G

  2. #2

    Join Date
    Dec 2014
    Posts
    1,157
    Thanks
    497
    Been Thanked: 1,977 Times

    Default

    Quote Originally Posted by gardro View Post
    Ive got quite a few transformers and switches lying in the parts bin so it occurred to me I might as well go and build a switched fan controller.

    For the design I need some information from fellow growers based roughly on their minimum fan speeds in terms of %

    Do we know what voltage the fan is running at when on the minimum speed? This will help my choose the right secondary voltage

    Has anyone measured the power at this minimum speed to see what the effect is on current draw?

    Theory says that if you half the speed, you will reduce the power 8 times

    Cheers
    G
    Google is your friend but tbh id just buy a variac.

    Sent from my SM-G955F using Tapatalk

  3. The Following User Says Thank You to BritishBotanics For This Useful Post:

    Karsa (02-12-17)

  4. #3

    Join Date
    Nov 2017
    Location
    De Pijp
    Posts
    10,915
    Thanks
    28,179
    Been Thanked: 46,725 Times

    Default

    Quote Originally Posted by MrNice View Post
    Google is your friend but tbh id just buy a variac.

    Sent from my SM-G955F using Tapatalk
    Thanks but variacs are a bit pricey and I'm on a bit of a budget. Got ones tapped at 110, 96, 48, and 24v so could be a decent level to run the fan at for min.


    Sent from my Pixel using Tapatalk

  5. #4

    Join Date
    Dec 2014
    Posts
    1,157
    Thanks
    497
    Been Thanked: 1,977 Times

    Default

    Quote Originally Posted by gardro View Post
    Thanks but variacs are a bit pricey and I'm on a bit of a budget. Got ones tapped at 110, 96, 48, and 24v so could be a decent level to run the fan at for min.


    Sent from my Pixel using Tapatalk
    Well first youll need to know how many amps it can handle. If i remember correctly :/ .... V = IR. So watts/voltage = amps.

    Sent from my SM-G955F using Tapatalk

  6. #5

    Join Date
    Sep 2017
    Location
    Laederon Plateau on the northern edge of the continent of Genabackis.
    Posts
    3,675
    Thanks
    7,272
    Been Thanked: 10,313 Times

    Default

    Variac is a tenner (£10-12) here.... How much is it for you?

    Sent from my G8141 using Tapatalk

  7. The Following User Says Thank You to Karsa For This Useful Post:


  8. #6

    Join Date
    Nov 2017
    Location
    De Pijp
    Posts
    10,915
    Thanks
    28,179
    Been Thanked: 46,725 Times

    Default

    Quote Originally Posted by Karsa View Post
    Variac is a tenner (£10-12) here.... How much is it for you?

    Sent from my G8141 using Tapatalk
    Seem to be 50 to 100 pal

  9. #7

    Join Date
    Nov 2017
    Location
    De Pijp
    Posts
    10,915
    Thanks
    28,179
    Been Thanked: 46,725 Times

    Default

    Quote Originally Posted by MrNice View Post
    Well first youll need to know how many amps it can handle. If i remember correctly :/ .... V = IR. So watts/voltage = amps.

    Sent from my SM-G955F using Tapatalk
    The transformers I have are 100VA and 200VA so should be fine

    4inch rvk runs around 40W ish

    Once voltage stepped down the power is reduced significantly so current wont be an issue. On start up perhaps but can tweak the capacitor

  10. #8

    Join Date
    Sep 2017
    Location
    Laederon Plateau on the northern edge of the continent of Genabackis.
    Posts
    3,675
    Thanks
    7,272
    Been Thanked: 10,313 Times

    Default

    Quote Originally Posted by gardro View Post
    Seem to be 50 to 100 pal
    282602208505 or are you wanting one like these ones 132193059882

    Sent from my G8141 using Tapatalk

  11. The Following User Says Thank You to Karsa For This Useful Post:

    gardro (02-12-17)

  12. #9

    Join Date
    Nov 2017
    Location
    De Pijp
    Posts
    10,915
    Thanks
    28,179
    Been Thanked: 46,725 Times

    Default

    That first one is a light dimmer which can work but can be a bit nasty too with humming and harmonics which can cause problems for other electronics in your house

    The second one is what I want to build - not really a variac but more of a multi tapped transformer so you can switch from 240 to 110, 96, 48 etc

    Variacs are continuously variable like this 332174705704 so can select any speed rather than 5 speeds in your second one

  13. #10

    Join Date
    Dec 2014
    Posts
    1,157
    Thanks
    497
    Been Thanked: 1,977 Times

    Default

    Have a look on electronics forums. But i wouldnt bother controlling a 4". They are near silent on full. So theres no need to controll it.



    Sent from my SM-G955F using Tapatalk

Page 1 of 2 1 2 LastLast

Tags for this Thread

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
  •  


THCtalk.com Disclaimer - You must be over 18 years old to view/use this site .THCtalk.com does not encourage growing Cannabis or possessing Cannabis. Learning how to grow Cannabis instructions should be for educational purposes only. All Information contained in this web site is for: Historical reference, Scientific reference and Educational purposes only. Visitors to this website are advised against breaking the law as It is illegal to smoke, grow, or possess cannabis in the UK and some US States