Need help desiging A "Kick Start" For a PWM controller. - Page 1
Forum section: electronics / projects

author: xReM1x
author_rank: Regular Contributor
timestamp: July 28, 2014, 09:48:22 pm
content: hey y'all. I (unfortunately) bought pwm controller from eBay and there is no schematic on the intrent, And I wanna add to this controller a "kick start"kick start :http://www.overclockers.com/forums/s...&postcount=822http://www.overclockers.com/forums/s...postcount=1214So, I dont have schematics or anythingfor the contoller I bought so I need a circuit Separate from the controller, a circuit I could add Additionally to the pwm controller.I might could try to make the schematics just by looking at the connections..I use fan model PFC1212DE. it draw 4.80A at the start.--They made it so You have to desolder the inputs to see the mosfet \ transistor..expect the mosfet or transistor there are :IN5 something big schottky diode.555NE timerZener Diode2 470uF electrolytic capacitors2 non polrazied small capaictors in series.1 non polrazied small capaictorcouple of resistors and potentiometer.Btw, in the input its not actually a transistor\mosfet its a voltage regulator, probaly 7812.

author: NiHaoMike
author_rank: Super Contributor
timestamp: July 29, 2014, 12:46:25 am
content: That kind of PWM driver will not work with most ECM motors., at least not without modification.

author: LukeW
author_rank: Frequent Contributor
timestamp: July 29, 2014, 01:52:27 am
content: Looks like your classic 555 PWM basic circuit. You can find examples of other schematics that are very similar online, and trace out the circuit you've got.For a "kick start" you could hold the 555 in reset for a moment with a capacitor connected to pin 4, and then as that capacitor charges up once the system is powered up, then the 555 will start and the motor will slow down.

author: xReM1x
author_rank: Regular Contributor
timestamp: July 29, 2014, 11:48:57 am
content: Quote from: LukeW on July 29, 2014, 01:52:27 amBut how do I add this? I cant solder anything there is mask and no holes, Is there something sperate?Somebody told me this :"There is a trick you can try though and it doesn't need any modification to the board at all. You need diode (1N4001 through 1N4007 will work) a 10K resistor and another capacitor. The capacitor value depends on the power requirenment of the fan which I have no information about but I would suggest 470uF as a starting value for experiments. Increasing the value will give a bigger 'kick' to the fan when the power is turned on.Wire it like this:The cathode of the diode (banded end) goes to the positive end of the new capacitor. The anode end of the diode goes to the PWM output connection, the one nearest the mounting screw in the corner of the board. The negative end of the capacitor goes to the negative supply input connection. The 10K resistor is wired across the capacitor.This is how it works: When power is first applied the capacitor will be discharged and will draw current through the fan and new diode until it has charged up to supply voltage. This extra burst of current is what 'kick starts' the fan. The diode prevents the new capacitor discharging back into the PWM transistor when it conducts so the process isn't continuously repeated. The new resistor is there to slowly discharge the capacitor so it can produce a fresh kick start after a few seconds of the power being removed and reapplied."But I dont know how to wire the fan, I built the circuit but were do I put the fan..