Browse Forums General Discussion Re: Ceiling Fan - underpowered 3Feb 26, 2017 7:27 pm 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: Ceiling Fan - underpowered 5Feb 26, 2017 8:40 pm Is there 300mm space between the blades and the ceiling? The rake should be correct out of the box but have you checked it? 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: Ceiling Fan - underpowered 6Feb 26, 2017 9:11 pm SaveH2O Is there 300mm space between the blades and the ceiling? This distance (the distance between the blades and the ceiling) is determined by the physical length of the down rod. The downrod and ceiling mount makes up part of the product itself - it's not something that can be altered (intentionally or mistakenly). To answer your question, the distance between the blades and the ceiling is 200mm. But again, it's not something that can be altered - I don't believe this is the cause of the problem. Re: Ceiling Fan - underpowered 7Feb 26, 2017 9:12 pm A few facts to re-cap: F1) According to the product specifications, the Arlec fan should spin at 200 RPM. F2) The Arlec fan is only spinning at 145RPM (at the maximum speed setting) So that key question I have here is: 6) Is it possible that the power being supplied to the fan (ie: the house wiring/circuit, the installation wiring that was installed by the electrician) is causing the fan to be under powered, and thus spinning at an RPM less than the product specification? 7) Or conversely, is the problem (lack of power / lack of RPM's) within the fan itself? Re: Ceiling Fan - underpowered 8Feb 26, 2017 11:54 pm I cannot comment about whether or not the electrician has made an error when doing the installation, I can only comment on airfoil characteristics and what may affect the efficacy of yours. It is 'possible' that the speed control is faulty. The optimum efficacy from the blades to the floor with an accessible boundary swept layer is 2.5 m. The optimum distance from the blades to the ceiling is 300mm. 200mm is restrictive for a decent fan. The optimum rake is 6 degrees. The blade's pitch needs to match the motor's power for peak efficiency. If the pitch is too steep, the motor will struggle, too shallow and it won't move much air. Your fan has a small 45W motor and the foil pitch will almost certainly be shallow. Most fans cannot perform at peak efficiency if the above conditions are not met and this is the case in most Australian houses. There are some very good fans available that have aerofoils engineered to aeronautic principles. If you are able, try to find a link to the BigAss fans design and testing department and see how a good fan is designed. The Arlec fan is very basic in that it has flat blades that generate high drag wingtip vortices and bleed, the efficacy losses compounded by the close airfoil/ceiling separation zone. Increasing the revs from 146 rpm to 200 rpm may not give you the incremental improvement that you might be expecting. 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: Ceiling Fan - underpowered 9Feb 27, 2017 6:01 am Hi SaveH2O, thanks for your response, there was some very good details/analysis about the Arlec fan. How about this HPM fan? Based on the same analysis that you did on the Arlec fan, how do you think this one would perform? https://www.bunnings.com.au/hpm-1200mm- ... n_p4441507 Re: Ceiling Fan - underpowered 11Feb 27, 2017 6:34 pm Link is no good. What is your ceiling height? A good house ceiling fan needs about 300mm space between the ceiling and the blades. The Arlec would have 200 mm because the small motor and the blade design does not require more. The short down rod would have sent a very BIG signal to me and the electrician should have known that and questioned your product choice. Beware of people telling you to choose a fan with longer blades, bigger fans require a greater space between the blades and ceiling and are more suited to higher ceilings. Longer blades also generate more noise due to the blade's higher tip speed. Fans also need an open lower swept boundary layer for peak circulation cooling efficiency because that is where the coldest air is. Having a fan sitting over furniture is less efficient than having it sit over an open area. Always give any fan its best opportunity to perform well. BigAss fans are superbly designed to aeronautic principles and are highly efficient and economical. The large BigAss fans in Bunnings incorporate numerous aerodynamic narrow blades that add to the swept solidity ratio without increasing drag whereas wide blades have greater surface air flow separation (pressure drag). The winglets that you will also see at the end of the aerofoils are there to reduce bleed and parasitic vortex drag. I am sure that you have seen passenger jets also fitted with winglets, they are fitted for the same reason. If you see a fan with multiple narrow blades and winglets, it has been designed for engineered excellence rather than point of sale appeal like fans with wooden rattan blades are. Fans are bought to serve a purpose and if you want good function, you have to be prepared to invest more to buy engineered quality. I personally like the BigAss Haiku range, not only for their efficiency but also because they are a modern stylish feature, not just an attachment. 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Any electricians here please help. 1) Will the Fan need separate switch to ON/OFF/Speed eventhough it comes with Remote 2) how about… 0 1204 My home office is hot with computer equipment running virtually 18 hours a day. When it gets unbearably warm I simply step out of my door into the living area which is… 0 5123 Unless the room is for storage then it's non compliant BCA V2 2019 S3 P3.8 You have 2 options 1. The builder deconstructs the section and rebuilds as per plan /… 7 10683 |