Smoked speed controller!
04-19-2003, 10:29 PM
#1
Smoked speed controller!
OK my fault, i smoked my GWS 2 amp controller today. Added a extra cell to bring my battery pack up to seven cells on a gws 300c motor/gear box with 10-8 prop on my e starter. Took advice from fellows kind enough to respond to a previous post and advanced the timing on the stock motor. Flew several times yesterday with just 6 cell packs with no problem. if a little is good, then more is better, Right?? Added the extra cell to the pack, plugged in the motor with no prop, everythings cool. Put the prop on throttled up and smoked the controller. Need some controller recomendations please. using AA 1300 NiMH cells
thanks
z-123
thanks
z-123
04-21-2003, 01:24 AM
#2
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Speed control
Obviously you CANNOT put 5-10amps through a 2amp ESC and expect it to cope with that sort of current!
I haven't tried a 10x6 with 7-8 cell 1100NiMH, but my measurements for my 300C-D 6.6:1 with an 11x7, on 7-cell 950KAN NiMH and 8-cell 600 NiCd, will be close enough to indicate what you are up against.
Peak current draw with 7-cell 950 was 8.7amps (66W), with 8-cell 600 it was 10.7amps (94W) - obviously you are not going to be able to sustain such currents without destroying the motor and battery, but cruising currents are going to be around 5-6amps anyway.
If you are going to use 7-8 cell 1100mAh battery packs you'll be drawing similar currents on full throttle, so you need to get an ESC which can cope with at least 15amps to be on the safe side. I would recommend going even a little bigger - in my view THE BEST ESC's out there are those in the Castle Creations Pixie series [they don't make the Pixie 14 any more, but buy the Pixie 20 - it doesn't weigh any more than other brand 15amp controllers and you are always better off going for more rather than too little!]
You can get the Pixie 20 direct from www.castlerc.com for $39.95.
Hope this helps out, Cheers, Phil
I haven't tried a 10x6 with 7-8 cell 1100NiMH, but my measurements for my 300C-D 6.6:1 with an 11x7, on 7-cell 950KAN NiMH and 8-cell 600 NiCd, will be close enough to indicate what you are up against.
Peak current draw with 7-cell 950 was 8.7amps (66W), with 8-cell 600 it was 10.7amps (94W) - obviously you are not going to be able to sustain such currents without destroying the motor and battery, but cruising currents are going to be around 5-6amps anyway.
If you are going to use 7-8 cell 1100mAh battery packs you'll be drawing similar currents on full throttle, so you need to get an ESC which can cope with at least 15amps to be on the safe side. I would recommend going even a little bigger - in my view THE BEST ESC's out there are those in the Castle Creations Pixie series [they don't make the Pixie 14 any more, but buy the Pixie 20 - it doesn't weigh any more than other brand 15amp controllers and you are always better off going for more rather than too little!]
You can get the Pixie 20 direct from www.castlerc.com for $39.95.
Hope this helps out, Cheers, Phil
04-21-2003, 01:27 AM
#3
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Whoops
Sorry, misread your battery size - 1300 not the 1100 I quoted. But the same comments apply - perhaps moreso, 'cos your 1300's will be able to supply even more current ! Cheers, Phil
04-21-2003, 01:53 AM
#4
Smoked speed controller!
Thanks Doc.
was a little concerned when turning the timing up on the motor that i might be pushing things but just hadda go with what i had.
A friend at the flying field let me try a 15 amp GWS controller today. Performed like a champ. With the 7 cell 1300 mah AAs and the timeing turned up a bit perfomance was very good with 9 mins. of really good power and another 3-4 mins before the BEC kicked in. It will now do loops and split Ss from level flight and will now climb into a stiff breeze with no problem.
I will take your advice though and see about getting a controller closer to 20 amps just to be on the safe side. I wonder if with the modified motor if i should drop down on the propsize or go with a lower gear to take better advantage of the rpm increase the advanced timing gives. I feel that the 10x8 on the 300c gearbox might be a bit much for the motor.
Thanks again
was a little concerned when turning the timing up on the motor that i might be pushing things but just hadda go with what i had.
A friend at the flying field let me try a 15 amp GWS controller today. Performed like a champ. With the 7 cell 1300 mah AAs and the timeing turned up a bit perfomance was very good with 9 mins. of really good power and another 3-4 mins before the BEC kicked in. It will now do loops and split Ss from level flight and will now climb into a stiff breeze with no problem.
I will take your advice though and see about getting a controller closer to 20 amps just to be on the safe side. I wonder if with the modified motor if i should drop down on the propsize or go with a lower gear to take better advantage of the rpm increase the advanced timing gives. I feel that the 10x8 on the 300c gearbox might be a bit much for the motor.
Thanks again
