Si-Bore Posted March 22, 2009 Report Share Posted March 22, 2009 Hey guys I was out yesterday and when connecting the battery up to the magnet I impressively put the terminals on the opposite charges, frying the speed control. Thats the 2nd one I have done! I was then left with an unusable magnet as it was rotating too fast when I bypassed the control. The way round it in the past was to use a long wire to reduce current and that gives the perfect speed but its so heavy to carry that as well as the rest of the gear as you probably all know. Can anyone think of any way to simply reduce the speed other than a 6v battery or another speed control becuase at £20 they're a rip off. Especially when I fry them up like bacon! Cheers, Si Quote Link to comment Share on other sites More sharing options...
John_R Posted March 22, 2009 Report Share Posted March 22, 2009 You could always buy another one, and make a connector that can only go on one way, leaving the spades on the battery itself all the time. Quote Link to comment Share on other sites More sharing options...
Warlock Posted March 22, 2009 Report Share Posted March 22, 2009 Goto maplins.co.uk look on there for resistors etc etc. thats what i did. cost me about £3 to make a controller that does my lamps and my magnet. i have one i bought from shootwarehouse but not sure how waterproof it is so made some cheap ones. Quote Link to comment Share on other sites More sharing options...
J@mes Posted March 22, 2009 Report Share Posted March 22, 2009 you want these: tamiya connectors from any good model shop, about £2.50 and as above, find out what resistance the variable speed controller resistor is and buy one from maplins. Quote Link to comment Share on other sites More sharing options...
HW682 Posted March 22, 2009 Report Share Posted March 22, 2009 Hi, we have discussed homemade speed controller recently on here. The good ones use pulse width modulation (PWM) rather than just a variable resistor. It is certainly possible to control the speed with a resistor - but I doubt that cutting open your old controller will help to work out the correct value. If you or anyone else knows what current the motor draws, then we can work out a suitable resistor value for you. The irony is that if the controller contained a diode (maybe something like this) then it wouldn't be damaged by connecting it up the wrong way. An alternative to the good suggestion of using a polarised connector already suggested, would be to fit your own diode externally in the wire. HW682 Quote Link to comment Share on other sites More sharing options...
Si-Bore Posted March 22, 2009 Author Report Share Posted March 22, 2009 Thanks guys. I like the idea of permanently fixing the connectors so that it is impossible to wire it reversed especially when I am running about dodging incoming pigeon. Si Quote Link to comment Share on other sites More sharing options...
saunders.shoots Posted March 22, 2009 Report Share Posted March 22, 2009 i managed to fry mine aswell. all i did was call the company and they said open it up and simply change the fuse.!!!!! these cost about 10p from any hardware shop Quote Link to comment Share on other sites More sharing options...
Si-Bore Posted March 22, 2009 Author Report Share Posted March 22, 2009 Link to my magnet with speed control Above is the link to the magnet/speed controller that i use. Think its a cheaper speed controller without a fuse. I might give them a call and see if they can suggest anything. Cheers, Si Quote Link to comment Share on other sites More sharing options...
saunders.shoots Posted March 22, 2009 Report Share Posted March 22, 2009 o right ok. i think it would be worth getting one with a fuse then. off ebay or something if you keep blowing them up Quote Link to comment Share on other sites More sharing options...
Si-Bore Posted March 22, 2009 Author Report Share Posted March 22, 2009 Anyone tried these? Speed control Cheers Si Quote Link to comment Share on other sites More sharing options...
saunders.shoots Posted March 22, 2009 Report Share Posted March 22, 2009 that looks exactly like mine. does the job Quote Link to comment Share on other sites More sharing options...
deny essex Posted March 22, 2009 Report Share Posted March 22, 2009 Anyone tried these?Speed control Cheers Si yep i bought one . lasted 3 mins , guy said he will replace it, will see how long the next one lasts. Quote Link to comment Share on other sites More sharing options...
deny essex Posted March 22, 2009 Report Share Posted March 22, 2009 Useing a fixed wire resistor from an old ford escort heater motor as a back up till the next speed controler arrives, three speed and pence from a breakers yard, a good backup to carry around if a speed controler packs up on the day . Quote Link to comment Share on other sites More sharing options...
Agent36 Posted March 22, 2009 Report Share Posted March 22, 2009 Hi, If you PM me, I could help you out with your problem....I design and build this sort of stuff. The speed controller I do at the moment prevents you making the mistake you made by cross connecting at the battery. If you did cross connect then only the fuse will blow, protecting the circuit. regards Agent36 Quote Link to comment Share on other sites More sharing options...
Cranfield Posted March 22, 2009 Report Share Posted March 22, 2009 Been there , done that, so I have fixed mine so that the only connections I make is to the battery. With the positive and negative clearly marked, I haven't fried anything since. Quote Link to comment Share on other sites More sharing options...
HW682 Posted March 22, 2009 Report Share Posted March 22, 2009 If you did cross connect then only the fuse will blow, protecting the circuit. Why not protect it with a diode so that it doesn't blow anything? HW682 Quote Link to comment Share on other sites More sharing options...
Agent36 Posted March 22, 2009 Report Share Posted March 22, 2009 Why not protect it with a diode so that it doesn't blow anything? HW682 Hi, If you put a diode in series with the motor, then the motor will only get 11.3 volts. Assuming the battery is at 12volts and the voltage drop across the diode is 0.7 volts which is common for most power diodes. The way I have designed my circuit is such that in normal operation the full 12volts goes to the motor, if you connect the battery the wrong way round a reversed power diode in parallel with the fuse and battery passes the reversed voltage blowing the fuse protecting the rest of the circuit. If the current exceeds the fuse rating in normal operation, it will also blow protecting the circuit. Sorry for the technical jargon for those normal people. regards Agent36 Quote Link to comment Share on other sites More sharing options...
HW682 Posted March 22, 2009 Report Share Posted March 22, 2009 The way I see it is that if you are worried about that 0.7v, then you probably don't want a speed controller in the cicuit anyway. You could use a Schottky to half that value. Alternatively, it must be possible to design a circuit with a diode to protect the vunerable components and still apply full voltage to the motor if that was desirable. I am not knocking what you have done, if you are happy with it and it suits your needs then job done. But I suspect that the average user would probably prefer a controller that has a slightly slower maximum possible speed - but with the advantage that they don't have to worry about changing fuses if connected the wrong way round. HW682 Quote Link to comment Share on other sites More sharing options...
Agent36 Posted March 22, 2009 Report Share Posted March 22, 2009 (edited) Hi HW682, You know what some people are like, they would complain it did not operate at full speed. I had that sort of problem when I built some random timers about 5 years ago using a transistor rather than a fet! I was thinking of trying a thermal fuse in series with the diode, so nothing blows in that situation, what you think?. I did try a thermal fuse to protect the whole circuit, but the trip time was not fast enough to prevent damage to the fet, so went back to the good old fuse. I am glad there is another lecky on the forum! regards Agent36 Edited March 22, 2009 by Agent36 Quote Link to comment Share on other sites More sharing options...
HW682 Posted March 22, 2009 Report Share Posted March 22, 2009 Agent36, Yes, it is good to have a constructive discussion about a subject. I have to say that as a relative newcomer to pigeon shooting, I don't have a rotary of my own yet so I don't know whether the small voltage drop would be a problem or not. But as I said, my thinking is that if you wanted to run at full speed you wouldn't be needing the controller in the first place. I think the thermal fuse is always going to be slower than the semiconductor junction. Another option would be to create an "active diode" using a pass transistor or similar with a much smaller forward voltage drop. My impression from the forum is that peoples biggest gripe is blowing up the controllers altogether or having to change the fuses when out in the field. What we need is a bit of feedback from other users......as a general rule how fast do you operate the rotary compared to it's fastest maximum possible setting? Would you accept a slightly slower maximum possible speed to ensure it could not be damaged by connecting up the wrong way round? HW682 Quote Link to comment Share on other sites More sharing options...
Shabbyshot Posted March 22, 2009 Report Share Posted March 22, 2009 I find that my dads magnet is to much at top speed and seems to do more harm then good. I normally have it set about midway. It may just be that particular make of magnet, but it is much to fast at top speed. I have also blown a controller. SS Quote Link to comment Share on other sites More sharing options...
Agent36 Posted March 22, 2009 Report Share Posted March 22, 2009 HW862, I agree with you about the pole!! I would be good to get feedback on what people want. I think alot of people would rather have a low cost product rather than a medium priced one (i could be wrong). I try to build controllers at low cost without risking the reliability by cutting corners. I did think about using a microprocessor with a hall effect sensor and controlling the current in software. Just not got round to it yet. Like you said the way I have designed the protection is just one way to skin a cat. The speed of the magnet is down to the conditions in the field on the day, slowing it down or speeding it up makes all the difference. Some decoy types wont work unless the speed is correct, having a controller that allows the user to control the full range of speed without disconnecting and reconnecting reduces the chances of pulling connectors off. Another common problem with pigeon shooting electronics. I have tried to reduce that by soldering the connections. I have learnt that nothing is pigeon shooter proof..lol Regards Agent36 Quote Link to comment Share on other sites More sharing options...
Si-Bore Posted March 22, 2009 Author Report Share Posted March 22, 2009 Agent36,What we need is a bit of feedback from other users......as a general rule how fast do you operate the rotary compared to it's fastest maximum possible setting? Would you accept a slightly slower maximum possible speed to ensure it could not be damaged by connecting up the wrong way round? HW682 If mine is used with a 5m wire (to save weight) it runs way to fast. I would need a maximum of 75% of that speed a guess. Often just over half speed. I used it tonight with 40m of wire and it ran perfect speed but i hate having to carry that wore about just for that! Thanks Si Quote Link to comment Share on other sites More sharing options...
deny essex Posted March 26, 2009 Report Share Posted March 26, 2009 Anyone tried these?Speed control Cheers Si UP date from my comment in reply to si-bore , the guy from the link is very efficent on a replacement and helpfull, hopefully all sorted now for the next time out. Quote Link to comment Share on other sites More sharing options...
Beardo Posted March 26, 2009 Report Share Posted March 26, 2009 i blew my magtame the other day. just ordered one of those cheap ebay ones. Quote Link to comment Share on other sites More sharing options...
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