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Astro motor timing problems - (please help)
A few months ago, I changed the direction and timing on this .05 motor for a pusher configuration. The lowest current draw was 3.9 amps with no load on 7 cells. I thought that seemed a little high. (2.2 amps no load according to the printed info ). So I never flew it this way.
I recently wanted to put the direction and timing back to it's original setting. So I hooked up the ampmeter and reversed the endbell. The lowest current I could achieve was 3.9 amps on 7 cells. Am I completely missing something? The motor gets pretty darn hot if I let it run like this for a minute. I thought the static, no-load amps should be 2.2? BTW: I didn't just reverse the leads, I rotated the endbell 90% and put the setscrews back in. Any expert advise (regarding the timing) would be greatly appreciated! Thanks, -=h=- |
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OK, I just went through this.... my prob was that I could not find the "null" point, (of lowest amps. ) before hitting the end of the mechanical adjustment limit. Try to find a 6 volt pack, or preferably a regulated power supply that will maintain a regulated 6 volts (for the 035 - 05 - 15 motors) ,rotate the black center magnet (after removing the screws) 180 degrees (NOT 90 as you have stated) Now, here is the tricky part, you may have to REMOVE THE SCREWS COMPLETELY to rotate the magnet far enough to find the "null" point, record the (minimum) amps, add 10% of your run current ("cruise" current for sort flying, "max" current for full power flying) adjust for that value, install screws and go fly... You need some more hands to do this, the parts don't take to well to the "apart and flying around the shop" part if that happens, so be careful to hold the motor together. Wear gloves and eye protection.
Good luck! Dave |
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Okay thanks Dave,
Yes, you're right, 180 degrees - what was I thinking... I've achived the lowest current possible for this direction, which was 3.9 amps. I was just wondering if that was too high. I thought the lowest currect with no load would be closer to 2 amps. Again, thanks for the help. -=h=- |
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Make certain you're using the correct bolt holes when you change directions. Unless your motor is fairly old, there should be two sets of bolt holes; one is used for forward rotation, the other for reverse rotation. It will get hot when run with no load, so expect that (basically power is being turned into heat). With most of the sport motors you can simply advance the timing all the way (full mechanical adjustment) and be set pretty well, although it's worth checking to make certain you don't have too much advance. I don't usually see values as low as two amps on my motor for the minimum current draw - 3+ is more common in my experience, with 5 - 6 amps advanced.
Steve |
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Steve,
Thanks for responding to this. Yes, I used the reverse bolt holes. It's good to hear that others are getting about the same current range. I feel much better about it after reading your post. Since Astro doesn't give any indication which hole is which, (on this motor), I engraved very tiny "F" and "R" next to the holes. It would be nice if Astro did this for those of us who can't stop messing around with things Thanks again, Harry |
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Last edited by harryo; Feb 18, 2003 at 12:10 PM.
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Glad to help. I like the idea of engraving an "F" and an "R" on the endbell. Timing marks wouldn't be a bad idea either (most people end up engraving a few marks on their endbells anyway). Anything to help ease confusion is welcome.
Steve |
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Astro Timing
Steve, as an Astro person (7 of 'em 035-90) I find the re-timing a bit confusing. Some motors have 3 threaded holes in the end bell. And like the others in this thread I have difficulty in discerning the null amperage. Often it seems 'way too high and I search for another hole to plug into. It sure could be simpler. The advice give is to "reverse the endbell" and that really isn't enough. IMHO Tex.
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Tex,
I think it's only the FAI motors that have the three holes in the endbells (I saw this on a friend's FAI 15). I've timed enough 035/05/15 sport motors that it comes pretty naturally, but I don't generally get the same current values that are published. I just find the lowest current draw and then go up 1.5 - 2 amps (or usually full advance). Steve |
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I should have said 1.5 - 2 times the lowest current, rather and 1.5 to 2 amps. Sorry!
Steve |
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