Sam Thompson Posted March 13, 2009 Share Posted March 13, 2009 Does anyone know where I can find something to vary the speed of my fan (UK single phase is 240v 50Hz)? I use an old washing machine motor and some bits of a leaf blower which I've had for years. What sort of broken machinery should I scavenge in? I may not have mentioned it before but I live next door to a scrap yard, so there's a good chance of finding something. Quote Link to comment Share on other sites More sharing options...
jimbob Posted March 13, 2009 Share Posted March 13, 2009 make an air gate and run the motor wide open regulate the air flow with the gate Quote Link to comment Share on other sites More sharing options...
Sam Thompson Posted March 13, 2009 Author Share Posted March 13, 2009 I've got an air gate but I've never been able to make one that gives accurate control... I use it to turn the blast off while I'm hammering (it allows a little air in to keep the fire going). At the moment I'm using rubber tube with a g-clamp but the noise of the fan at full speed is annoying me and the only other plan is to put the blower outside the shed. This will transfer the annoyance to my neighbours whom I like. I've had several 'boxes with a knob on' that have done the job in the past but can't find one at the moment. Quote Link to comment Share on other sites More sharing options...
brianbrazealblacksmith Posted March 13, 2009 Share Posted March 13, 2009 I agree with Jimbob. You want control of your air flow, all the way on and all the way off and every thing in between no matter what your air source is. Quote Link to comment Share on other sites More sharing options...
Sam Thompson Posted March 13, 2009 Author Share Posted March 13, 2009 I've got an off switch to cut it off! I should mention that I use coke (Breeze) which goes out in about five minutes without a blast. What I need to do is keep the fire at a given size with the variable draught and use the gate to cut it down when I'm working without disturbing the power of the blast. Quote Link to comment Share on other sites More sharing options...
John B Posted March 13, 2009 Share Posted March 13, 2009 You can get a 1000w dimmer switch that you can use to control the motor speed from an electrical products wholesaler or electric supplies shop, be sure to specify 1000w rating Or if just using a slide valve, make sure there is a small hole (6 to 8mm) drilled through to allow a small draft of air through when slide is in closed position, this will allow fire to 'tick over'. And if you want repeatability for the slide valve position, notch the adjusting arm and put a blade edge support under the notched area, you can mark the desired position with a white fluid correction pen for reference. Quote Link to comment Share on other sites More sharing options...
jimbob Posted March 13, 2009 Share Posted March 13, 2009 does your forge have a dump gate to dump the ash ...if so you can prop it open when the blower is off ...the heat of the fire will draw air up thru it and keep the coke going when the air blast is off Quote Link to comment Share on other sites More sharing options...
Sam Thompson Posted March 26, 2009 Author Share Posted March 26, 2009 Thanks for the suggestion/reassurance John. It works well. Quote Link to comment Share on other sites More sharing options...
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