chris edwards 3 Posted June 7, 2013 Share Posted June 7, 2013 hi i am in the process of buying a second speed controler for my foxjet ( the first one failed completly resuting in a fire and the plane hitting a tree due no control what so ever) the person i brought it of suggested that i put a 100amp esc in it as this is what he had before in it, now i put a 100amp red brick esc in it and as i have said it failed completly after 3-4 minuets of flying. now the technical bit- the edf fan is a Wemotec Mini Fan 480 Pro the motor is a Jetscream 1400, thats 4000 Kva 6 pole and the lipos are 5s 4000mah nano techs with a 25-50c discharge any advice on the wattage/ampage the motor will be pulling and what amp speed controller would be the best that won't burn out. chris Edited By chris edwards 3 on 07/06/2013 22:25:38 Edited By chris edwards 3 on 07/06/2013 22:28:38 Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted June 7, 2013 Share Posted June 7, 2013 4000 kv, on a 6s pack ?? and in a little foamy designed as a chuck glider??? Crazy Even on 5s ( the maximum suggested voltage for that motor) the current will be over 110A, so if you are crazy enough to try and stuff circa 22V through it, expect more smoke. Edited By Tim Mackey on 07/06/2013 22:48:07 Quote Link to comment Share on other sites More sharing options...
chris edwards 3 Posted June 8, 2013 Author Share Posted June 8, 2013 might not have made the model too clear but it is this instead of the little foam glider. going on your post time would a 120amp+ esc be better than the 100amp esc i got suggested buy the person who gave it to me? Quote Link to comment Share on other sites More sharing options...
John Privett Posted June 8, 2013 Share Posted June 8, 2013 Chris, do you have a wattmeter? (And one that reads high enough if you have!) Whatever the theory/best guess suggests, I'd want to see what the actual figures were before committing to flight a model that could be about to let the magic smoke out of another ESC - even a relatively inexpensive one! Quote Link to comment Share on other sites More sharing options...
chris edwards 3 Posted June 8, 2013 Author Share Posted June 8, 2013 no i don't have a wattmeter as when i am setting up a electric plane i always over spec the esc but with this model i just went on the word of the person who gave me the plane. he had a castle creation 100amp job when he had it but the castle creation esc's are way out of my price range hence the reason for buying the ceapest esc i could find. i have been told by the people at my club that there is a equation to work out the watts the motor will be drawing but im not too sure what this is. Quote Link to comment Share on other sites More sharing options...
John Privett Posted June 8, 2013 Share Posted June 8, 2013 I doubt you'll find any equation that you could easily use. Many electric flyers would argue that a wattmeter is not optional, but essential. The way electric motors work, as you increase the load on them (by using bigger and bigger props) the current drawn will increase, almost without limit - until something (motor, ESC or battery) is pushed beyond its capabilities and goes 'pop'. So the difficult part of any equation you might find will be determining the load the prop (or fan) is putting on the motor. Another issue is that expensive ESCs may be rated conservatively compared to cheap ones. A 100A ESC will not run forever at 99A and suddenly give up at 101A. There's a curve there, and it might be the marketing department that decide whether a particular item is described as a 100A ESC or a 120A one! So the same item with an expensive label might have a lower number on it as they know their customers demand total reliability and will pay for it. Whereas the same item with a cheap label may have a bigger number on it as that helps it sell and their customers may be more tolerant of failures. So what I think I'm saying is that a 100A Castle Creations ESC may well be ok in the same model where a 100A 'cheapy brand' ESC might only last a few minutes. Quote Link to comment Share on other sites More sharing options...
Daithi O Buitigh Posted June 8, 2013 Share Posted June 8, 2013 To work out the power you need at the very least an ammeter - Power in Watts is simply voltage supplied multiplied by the current draw (in Amps) I would strongly recommend a wattmeter though (or one of the combo jobs that does other things as well). I've one that measures power, current, checks battery voltages and also measures RPM (and also has a temperature probe) Quote Link to comment Share on other sites More sharing options...
chris edwards 3 Posted June 8, 2013 Author Share Posted June 8, 2013 i know that my dad has a electric test meter that does all matter of things, failling this could you suggest a sutable wattmeter/test meter that i could get. Quote Link to comment Share on other sites More sharing options...
Daithi O Buitigh Posted June 8, 2013 Share Posted June 8, 2013 I've one of these (the tacho isn't the best though as it needs to be very close to the prop and electric light interferes with it) but at a few pence over 26 quid, it's very useful Quote Link to comment Share on other sites More sharing options...
chris edwards 3 Posted June 8, 2013 Author Share Posted June 8, 2013 i think i might have to invest in one of these as you as at just over £26 you carnt reall go wrong. when testing the ampage/wattage does this test meter go inbertween the lipos and the esc or betwen the esc and the motor? Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted June 8, 2013 Share Posted June 8, 2013 YOU NEED A WATTMETER. If u insist on putting 6s thro the motor/fan unit, then get a 150A speedo. Quote Link to comment Share on other sites More sharing options...
Peter Beeney Posted June 8, 2013 Share Posted June 8, 2013 Chris, - Assuming your Jetscream motor is developing 1800 watts, 2000 maybe if you’re really pushing it on full throttle and fresh batteries, then the current flow on 5S would equate to around 97 - 108 amps; so it looks as though a 100A ESC might be at best marginal and at worst history. Sorry, I guess you’ve been there and done that already. If these power levels are indeed in this sort of area then even a 120A ESC is a bit of headroom and that’s it. And from what I’ve seen at our patch this could be what you are looking at. I’d certainly consider trying to arrange a nice through draught if possible. If you consider that 1800 watts becomes 2.4 BHP, somewhere midway between the max power of a 75 and a 95 OS AX i/c engine, then I reckon this model is, to say the least, a bit brisk down the home straight; and also round the bends, for that matter. But I’m sure you are already aware of this, too. A couple of points, electric light will probably affect most tacho’s, it’s one way of checking the calibration. If you use one in electric light, shine a good torch though the propeller, that will cancel the 50 Hz. It will also improve the tacho pickup, more positive from a distance. Wattmeter goes between battery and ESC, you need a special wattmeter to measure 3 phase AC. That's the three motor wires. Good luck! PB Edited By Peter Beeney on 08/06/2013 13:32:05 Quote Link to comment Share on other sites More sharing options...
chris edwards 3 Posted June 8, 2013 Author Share Posted June 8, 2013 so at least i need to look for a 120amp esc, any suggestions which one, remeber im on a limited budget. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted June 8, 2013 Share Posted June 8, 2013 chris This test (its a pdf file) by RC Universe shows your motor can draw 110A on a 5s so a 100A ESC will not be sufficient. You are working with quite a high power installation (1800W = 2.5 hp !) so there is little tolerance for errors. The consequencies of a failure get seriously expensive and potentially dangerous. You have to invest in the right test equipment. Is this your first EDF? Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted June 8, 2013 Share Posted June 8, 2013 Posted by chris edwards 3 on 08/06/2013 13:34:40: so at least i need to look for a 120amp esc, any suggestions which one, remeber im on a limited budget. Could have sworn I said 150A Oh well, I tried to help. Quote Link to comment Share on other sites More sharing options...
chris edwards 3 Posted June 8, 2013 Author Share Posted June 8, 2013 sorry didnt notice that, a 150amp should give a bit more head room. not its not my first EDF, it my fourth one, carnt stop buying them Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted June 8, 2013 Share Posted June 8, 2013 Yes they can be addictive can't they VFM Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted June 9, 2013 Share Posted June 9, 2013 chris I must say my defintion of 'a limited budget' would not cover such a powerful set up but I bet it is nonetheless very impressive! Quote Link to comment Share on other sites More sharing options...
chris edwards 3 Posted June 9, 2013 Author Share Posted June 9, 2013 simon when the jet was in the air it was very impressive and flew a treat which is why i was so annoyed when the esc when up in smoke. as im sure you know im only 16 so anything take me a while to save up and buy, which is why i have the limited budget. normally i would not be able to afford a plane with this sort of set up but because i got given it i only needed the esc and a recever to get it in the air. Watch your language, please - remember the C of C! Edited By Pete B - Moderator on 09/06/2013 14:10:21 Quote Link to comment Share on other sites More sharing options...
chris edwards 3 Posted June 9, 2013 Author Share Posted June 9, 2013 sorry got a bit carryed away Quote Link to comment Share on other sites More sharing options...
Reno Racer Posted June 9, 2013 Share Posted June 9, 2013 Why 5S? i have similiar weight/drag EDFs designed for 70mm fans running on 4S lipos, both my EFlite F-86 Sabre and Ziroli Turbinator -E are running Change Sun 10 blade 70mm fans on 4S 3000mah lipos and 70A or 85A ESCs. Both jets will top 120+ mph and converatively gives a 7min flight time; 800 watts and just over 58 Amps. Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted June 9, 2013 Share Posted June 9, 2013 Its worse than that - hes using 6S. Read the earlier posts. Quote Link to comment Share on other sites More sharing options...
chris edwards 3 Posted June 9, 2013 Author Share Posted June 9, 2013 tim im not too sure where you have read im using 6s but im definatly using 5s 4000mah and the only resons im using them is 1) the plane came with them and 2) i don't have any 4s lipos big enough or with a high enough discarge. Quote Link to comment Share on other sites More sharing options...
WolstonFlyer Posted June 9, 2013 Share Posted June 9, 2013 Hi thereThis PDF has a test of the Jetscream 1400 motor, their test rig has a Castle Phoenix 125A ESC and in the test data table for test 2 it shows a max current of 115A from a 5S pack.**Link to pdf file from RCUniverse**I would personally suggest a 150A ESC at least but you should really get a Watt/Amp meter and double check. Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted June 10, 2013 Share Posted June 10, 2013 Posted by chris edwards 3 on 09/06/2013 21:19:18: tim im not too sure where you have read im using 6s but im definatly using 5s 4000mah and the only resons im using them is 1) the plane came with them and 2) i don't have any 4s lipos big enough or with a high enough discarge. Ah, OK, sorry Chris, could have sworn I read it as 6s. Must get new specs Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.