Burton Posted July 15, 2013 Report Share Posted July 15, 2013 Thought maybe some of y'all might be electric gurus and be able to help me out. I know 12V really well, but this household wiring is still new to me. Gonna wire my paint booth fan this week, and would like some sort of speed control on it, rather than just have it be off or full tilt. Fan is 110V and 3.5Amp max. Can I just go buy like an adjustable light dimmer type switch as long as it's beefy enough to handle the 3.5 amps? Or do I need some sort of special type of fan speed adjuster? Link to comment Share on other sites More sharing options...
ucw458 Posted July 15, 2013 Report Share Posted July 15, 2013 (edited) A dimmer switch isn't a great choice. It will work somewhat but I've had limited success with them. The last time I used a dimmer switch on an AC motor I burned out the motor windings. There is however a PWM speed controller for up to 5 amps that looks just like a dimmer switch. I'll see if I can find one online and post it for you. Mcmaster has a few optionshttp://www.mcmaster.com/#fan-speed-controls/=nmtvfe Just FYITo vary the speed of an AC motor you don't want a variable resistor lowering the voltage. AC motors don't like running under 100 volts. They tend to overheat when you do that. Instead you vary the frequency. House current is 120 volts at 60 Hz. All AC motor speed controllers vary the Hz to control the motor speed. They do that with PWM. Edited July 15, 2013 by ucw458 Link to comment Share on other sites More sharing options...
ucw458 Posted July 15, 2013 Report Share Posted July 15, 2013 Here's a cheaper one,http://www.fruitridgetools.com/storefrontprofiles/processfeed.aspx?sfid=136763&i=257439347&mpid=8171&dfid=1&gclid=CMaX5ZD8sbgCFS_ZQgod4XsAwg You can probably find one locally at a home improvement store under the catagorie of fan speed control. Link to comment Share on other sites More sharing options...
wrngwae Posted July 15, 2013 Report Share Posted July 15, 2013 ^ what Jeff said you neet to lower the hz not the voltage. Link to comment Share on other sites More sharing options...
jszucs Posted July 15, 2013 Report Share Posted July 15, 2013 Yeah and make sure the fan motor can handle doing so. Depending on the type of fan motor some like the one's in a furnace are controled based on the way they are wired. IE the fan will have 3 diffrent inputs and each of the 3 is a speed. Link to comment Share on other sites More sharing options...
PDodson Posted July 16, 2013 Report Share Posted July 16, 2013 Let that thing blow, If it was my shop and I had a 110v fan I would just let it blow, I would only put a speed control on a 220v fan Link to comment Share on other sites More sharing options...
IntercooledFlatty Posted July 16, 2013 Report Share Posted July 16, 2013 http://www.industrialfansdirect.com/IND-FA-EF-GP/LFI-S18-FVD.html Link to comment Share on other sites More sharing options...
Burton Posted July 16, 2013 Author Report Share Posted July 16, 2013 Here is a link to the actual fan I got... I got the 20" version.... http://www.ebay.com/...984.m1497.l2649 All it says about a speed control is this: Variable speed capable – Must use variable speed control (Not Included) I contacted the seller and they don't offer one or know where to get one, and I'm not sure about if it's a 3 speed variable, or an ifninately adjustable variable speed. I'm starting to lean towards Paul's line of thinking LOL "Let that thing blow, If it was my shop and I had a 110v fan I would just let it blow, I would only put a speed control on a 220v fan". Link to comment Share on other sites More sharing options...
slowquest Posted July 16, 2013 Report Share Posted July 16, 2013 I'd go with Paul's advice also. If it is too much (when is it ever too much?) then look into a speed controller. Don't create an issue where none exists..... Link to comment Share on other sites More sharing options...
jszucs Posted July 16, 2013 Report Share Posted July 16, 2013 Your not using it for the paint booth just ventilating the shop? If your using it for the booth your going to want to control the flow. Sometimes you want a bit of draft sometimes you want it to just move enough air your not fumigating the booth and leaving overspray to settle everywhere. Link to comment Share on other sites More sharing options...
Burton Posted July 16, 2013 Author Report Share Posted July 16, 2013 Yeah, I only worry that it will pull too much. Lots of air movement in a booth is a good thing, unless the movement is so much it doesn't allow all the paint to hit the car, and sucks it out first. That thing moves some CFMs and will exchange the air in my booth 2 times a minute. Painting in a 14mph cross wind is no bueno. Link to comment Share on other sites More sharing options...
jszucs Posted July 16, 2013 Report Share Posted July 16, 2013 Yeah, I only worry that it will pull too much. Lots of air movement in a booth is a good thing, unless the movement is so much it doesn't allow all the paint to hit the car, and sucks it out first. That thing moves some CFMs and will exchange the air in my booth 2 times a minute. Painting in a 14mph cross wind is no bueno. Set up a system to vent some from the booth and some from the shop? Then you can contorl how much it's sucking out? Link to comment Share on other sites More sharing options...
Burton Posted July 16, 2013 Author Report Share Posted July 16, 2013 (edited) This is for the paint booth only. It will be blowing directly outside, and will pull it's air from filters in 2 of the walls of the booth, that filtered air will come from the air inside the rest of the shop. I get a nice breeze thru the rest of the shop and have a big commercial grade pedestal fan for when the wind's not blowing. Eventually it will all be insulated and air conditioned. I'd probably be better off pulling my air from directly outside, but I'm not trying to cut out a bunch of holes in the steel walls of the shop. I'm gonna feel bad enough cutting a hole for that 20" fan LOL. The booth is in a corner of the shop, so two of it's walls are exterior walls. I don't understand air dynamics much, but can I change the overall speed of the flow or amount of flow by how many filtered air inlets I have? Or will that only affect the amount of flow at each inlet? Edited July 16, 2013 by Burton Link to comment Share on other sites More sharing options...
jszucs Posted July 16, 2013 Report Share Posted July 16, 2013 (edited) What I was thinking was a diverter that say sucked 1/2 from shop and 1/2 from booth still exausting outside. If you need more flow in the booth you can move diverter and suck less from shop 1/4 and 3/4 from booth ECT. You don't want to just block the flow as that puts strain on the fan to suck air then. Edited July 16, 2013 by jszucs Link to comment Share on other sites More sharing options...
Burton Posted July 16, 2013 Author Report Share Posted July 16, 2013 Yeah and make sure the fan motor can handle doing so. Depending on the type of fan motor some like the one's in a furnace are controled based on the way they are wired. IE the fan will have 3 diffrent inputs and each of the 3 is a speed. How can I tell which type of fan motor mine is? Can you tell from the link I posted. Now I'm starting to think I'm better off going ahead and installing the fan control, especially since they aren't super expensive, but I want to make sure I get the right kind. Plus I still have to install the fan and wire it, so it shouldn't be too much extra work to get it handled all at once. Link to comment Share on other sites More sharing options...
jszucs Posted July 16, 2013 Report Share Posted July 16, 2013 The fan you have is a variable speed one, not through hardwire. So you need a controller it won't change speed based on how you wireit. Looks like you will need something that will run like 120V AC @ 3.5A for the 20" fan. Something like this. http://www.hydrogalaxy.com/climate-control/exhaust-fans-circulators/speedster-variable-speed-control/?gclid=CIfWycTptLgCFYqZ4AodcmIAxg Link to comment Share on other sites More sharing options...
IntercooledFlatty Posted July 16, 2013 Report Share Posted July 16, 2013 Mark i would think you WANT to control the speed of the fan considering what you are doing. I called and talked to a tech ( after checking in with my electrician Paulie ) and he guided me towards that fan i posted. I also got the controller for the reason i can leave it on low when we have high humidity to keep moisture down as much as that fan will do. I'm looking to have it installed this weekend so i'll let you know how it goes Link to comment Share on other sites More sharing options...
Burton Posted July 16, 2013 Author Report Share Posted July 16, 2013 Mark i would think you WANT to control the speed of the fan considering what you are doing. I called and talked to a tech ( after checking in with my electrician Paulie ) and he guided me towards that fan i posted. I also got the controller for the reason i can leave it on low when we have high humidity to keep moisture down as much as that fan will do. I'm looking to have it installed this weekend so i'll let you know how it goes Yeah, it would probably be best to have some control over it. I'm gonna see if Home Depot has one tonight or tomorrow, but if not, I'll get one online. Link to comment Share on other sites More sharing options...
PDodson Posted July 17, 2013 Report Share Posted July 17, 2013 your gonna put that fan on a 20 amp circuit anyway, so I wouldnt worry about the fan pulling to much amperage, only way it would pull alot of amperage is if it got into a bind, but this fan is brand new so I would not worry to much about it they dont make 5 amp breakers, the min size breaker they have is a 20 amp so you will be good, I would also have that fan on its own breaker and not share it with anything else such as lights and or receptacles just my 2.6 cents Link to comment Share on other sites More sharing options...
Burton Posted July 17, 2013 Author Report Share Posted July 17, 2013 your gonna put that fan on a 20 amp circuit anyway, so I wouldnt worry about the fan pulling to much amperage, only way it would pull alot of amperage is if it got into a bind, but this fan is brand new so I would not worry to much about it they dont make 5 amp breakers, the min size breaker they have is a 20 amp so you will be good, I would also have that fan on its own breaker and not share it with anything else such as lights and or receptacles just my 2.6 cents Good to know. I was just planning on it being on the same breaker as the booth lights, but I was going to use a 30A breaker. I have 2 30A, and a 20A normal breaker, then I have 2 each of 20A and 30A breakers with "test" buttons on them. Are those GFI breakers or something? I've got a 20 spot breaker box and all those breakers, so it looks like I'll be buying the big roll of wire/conduit from Home Depot LOL. I had planned on the mixing room having it's own breaker too, so it looks like I'll be running 3 lines to that corner of the shop. Figures.... It would have to be the corner opposite the breaker box LOL. Link to comment Share on other sites More sharing options...
PDodson Posted July 17, 2013 Report Share Posted July 17, 2013 Good to know. I was just planning on it being on the same breaker as the booth lights, but I was going to use a 30A breaker. I have 2 30A, and a 20A normal breaker, then I have 2 each of 20A and 30A breakers with "test" buttons on them. Are those GFI breakers or something? I've got a 20 spot breaker box and all those breakers, so it looks like I'll be buying the big roll of wire/conduit from Home Depot LOL. I had planned on the mixing room having it's own breaker too, so it looks like I'll be running 3 lines to that corner of the shop. Figures.... It would have to be the corner opposite the breaker box LOL. yes those are gfi breakers, If it was my shop and they are already in there, I would put my receptacles on those breakers, it would not hurt anything to put the fan on the 30 amp breaker but it is not needed, and I prolly wouldnt share the lights with the fan, oh and you prolly need 12/2 MC cable, that will have a black, white and green, that should be good for fan, lights and receptcles Link to comment Share on other sites More sharing options...
Burton Posted July 17, 2013 Author Report Share Posted July 17, 2013 yes those are gfi breakers, If it was my shop and they are already in there, I would put my receptacles on those breakers, it would not hurt anything to put the fan on the 30 amp breaker but it is not needed, and I prolly wouldnt share the lights with the fan, oh and you prolly need 12/2 MC cable, that will have a black, white and green, that should be good for fan, lights and receptcles Yeah, That's the wire I've been getting... 12/2 with the flexible conduit already on it. The shop came with the large breaker box but only 2 plugs and 2 lights on a 20A breaker. A friend of mine gave me a small breaker box with all the breakers I mentioned before and a couple of plugs, so I'm using what I can of that since it was free. I'll use the normal breakers for booth lights, mixing room, and fan, then save those GFI breakers for when I put plugs in around my workbenches. Can I run regular plugs off the GFI breakers, or will I need to use GFI plugs too? Link to comment Share on other sites More sharing options...
ucw458 Posted July 17, 2013 Report Share Posted July 17, 2013 yes those are gfi breakers, If it was my shop and they are already in there, I would put my receptacles on those breakers, it would not hurt anything to put the fan on the 30 amp breaker but it is not needed, and I prolly wouldnt share the lights with the fan, oh and you prolly need 12/2 MC cable, that will have a black, white and green, that should be good for fan, lights and receptcles Not a good idea. 12 ga wire is not rated for a 30 amp circuit. You can melt the insulation off the wires before the breaker will trip. A 30 amp circuit requires minimum 10 ga wire. 20 amps is the max for 12 ga wire. Link to comment Share on other sites More sharing options...
PDodson Posted July 17, 2013 Report Share Posted July 17, 2013 Not a good idea. 12 ga wire is not rated for a 30 amp circuit. You can melt the insulation off the wires before the breaker will trip. A 30 amp circuit requires minimum 10 ga wire. 20 amps is the max for 12 ga wire.the code has changed, but I was just letting him know, The shop came with the large breaker box but only 2 plugs and 2 lights on a 20A breaker. A friend of mine gave me a small breaker box with all the breakers I mentioned before and a couple of plugs, so I'm using what I can of that since it was free. I'll use the normal breakers for booth lights, mixing room, and fan, then save those GFI breakers for when I put plugs in around my workbenches. Can I run regular plugs off the GFI breakers, or will I need to use GFI plugs too? yea burton you can use regular outlets on the gfi breakers Link to comment Share on other sites More sharing options...
ucw458 Posted July 17, 2013 Report Share Posted July 17, 2013 Just remember most house receptacles are wired with 15 amp breakers. There is a visible difference between 15 amp and 20 amp receptacles. If your electrical work ever gets inspected you could get dinged for mix and matching. 20 amp receptacles do cost more. That's why most homes get the 15 amp ones. 15 amp receptacle $0.68http://www.homedepot.com/p/Leviton-15-Amp-Duplex-Outlet-White-R52-05320-00W/202066670?N=1z11z3t#.UeZ8itJ1_xAhttp://www.homedepot.com/catalog/productImages/300/7e/7e4a0dea-e322-4c19-a7d0-7f52a62a9d00_300.jpg 20 amp receptacle $3.28http://www.homedepot.com/p/Leviton-20-Amp-Commercial-Duplex-Power-Outlet-White-R62-CBR20-00W/202066702?N=1z11yyo#.UeZ80dJ1_xAhttp://www.homedepot.com/catalog/productImages/300/1d/1d8b16f1-03f8-4be0-a84f-f0cd573280bd_300.jpg Link to comment Share on other sites More sharing options...
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