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  • Users: Axher
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  1. Axher

    24 volt dc fan pwm control

    Hi, I'm in the design process of a speed control for 3 24 volt dc fans with sensors input to a microcontroler. I'm using the pwm output of the microcontroler to control the 3 fans speed. I'm using a 24volt power supply for the fan using about 150 watt. My question is : Is there any reason I...
  2. Axher

    24VDC transformer power supply selection

    Hi itsmoked, Thanks for all the information. But I still have a question about the inrush current in the caps. Is there a simple way to limit the current to the cap? A resistor seem like a bad idea because of the 7A current. I was thinking of just choosing a bridge that can support more...
  3. Axher

    24VDC transformer power supply selection

    Hi, I building a 24vdc power supply at 7A ouput with four 2200uf capacitor for a total of 8800. I have some trouble selecting the right transformer for my application. Simulation give me a high peak current in the transformer but I'm not sure if this will make the transformer overheat and if...
  4. Axher

    help with 48v dc fan control

    Ok thanks that's what I will do and I will probably design my own because I already have a 48v transformer and everything else.
  5. Axher

    help with 48v dc fan control

    Ok I'm sorry about this your correct I did some more test and I only get about 2 amp on the line but the power factor is not that good would this be a problem to certified it in north america ? I would also like to know if there's a better solution to this thanks
  6. Axher

    help with 48v dc fan control

    Ok your right I'm gona start over. It's for a product that will be controled from a microcontroller with pwm output. The microcontroller will get data from different sensor like temperature, humidity, etc. I need to control 3 dc fan from the microcontroler. each fan is about 60 watt. So I...
  7. Axher

    help with 48v dc fan control

    Hi, itsmoked I'm not sure how to do this without a SMPS with PFC. I try to use a simple power conversion with a rectifier and a capacitor and transformer but the peak current that I was getting at the ac line was to high because of my buck converter at the output. Is there a cheap way to...
  8. Axher

    help with 48v dc fan control

    Hi, I'm currently in a design phase of a variable speed 48vdc control for a fan. I want to connect the fan on the ac line so i need a ac to dc converter. I found out that the best solution is probably to use a switch mode power supply for the firts stage and a pwm buck converter to control the...
  9. Axher

    buck converter

    Thanks everyone, so if I understand correctly if I want to use the HCPL-3180 ( http://www.avagotech.com/products/product-detail.jsp?navId=H0,C1,C5231,C4945,C4988,P93297 ) instead of using a IR2117 and adding a extra optocoupler to isolated my microcontroller I would have to had a bootstrap to...
  10. Axher

    buck converter

    Do I need a boot-strap circuits if I use a isolated 15v source for the mosfet gate driver ?
  11. Axher

    buck converter

    Hi, I'm in the design process of a non-isolated buck converter to get 70Vdc from the 115vac line and I have some trouble controlling my mosfet. I'm trying to control the mosfet from a microcontroller using a hcpl-3180 from avago technologie. The mosfet is on the high side, so I need a floating...

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