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Electric Stunt => Gettin all AMP'ed up! => Topic started by: Randy Powell on April 09, 2013, 09:04:08 PM
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Any examples of an electric test stand? I'd like to set this all up and see it run before I stuff it in the nose of the plane.
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My test stand.
JCP
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Do not run motor on test stand more then few seconds. Our setups are overloaded in static air and it can easily burn. And if, then use 2" smaller prop.
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I mostly just wanted to put everything together a turn it on to make sure I did everything right before putting it all in a plane. A few seconds is all I need.
Thanks for the pictures.
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Hello Igor's
What can burn when static testing? The motor due to increased load, or the ESC due to added current being drawn from over loaded motor? Both? I ask this as we recently had an ESC overheat and catch fire about 2 minutes in on a first flight of a profile. I am still trying to figure out why this happened, and tend to believe it was a defective ESC. Glad it did not happen on a full body stunter!
Sorry for the detour Randy, back to you and your test stand query ;D
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Static current at the desired RPM setpoint typically consumes more than 4/3 of the average flying current; sometimes more.
Regards,
Dean Pappas
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How is it more load when the prop is cavitating?
When you are running it in water? Props don't cavitate in air.
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Hello Chris,
It is difficult to say, but usually it is motor which burns first. However we have experience with situation when one component takes another, and then whe you exchange that "bad" then it will take also another (right Keith? :- ))) )
Overloaded motor (improperly selected motor for prop and power) can heat so much that magnets will loose strength. Motor will need even more current to keep RPM and it will go even quicker. Burned winding will confuse ESC and it will try commutate in improper time and that can kill also ESC. So they usually go together. And burned ESC can short also battery which can make nice firework VD~
But it could be caused also by deffective component - short between windings in motor coil can also heat motor or make erros in commutation, it can kill them also.
And defective transistor in ESC can do the same.
Those two last probles can be checked when motor is tested on test stand WITHOUT PROP. Motor running at full power (not with ESC with governor) without load should take defined "no load current" which should be stated in motor specifications. Weak magnes, short between coils or deffective ESC will make that current signifficantly higher. Do not use such components.
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For what it's worth when I run a motor on a test stand I control the ESC with a servo tester. They are under 10$ on eBay.
http://www.ebay.com/itm/Free-US-Ship-ESKY-EK2-0907-Servo-Rc-Hobby-Auto-Tester-Adjuster-Motor-ESC-Tester-/281017376075?pt=US_Radio_Control_Control_Line&hash=item416df0dd4b#ht_2371wt_954
This gives me control without delays. Of course it does not bypass the rpm set mode in a programable speed controller. However I use a KR timer and a speed controller that does not have a RPM set mode. Another use is to sort out problems. By eliminating the timer you can ascertain if the problem is in the timer or in the ESC.
Pictured below is the servo tester I use. It is my own design but it cost more to build than you can buy one on eBay. All are easy to use. You just plug it in place of the timer and twist the knob.
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Thanks for the response Igor. I suspect it may have been a defective ESC. The motor is an E-Flite 25, with an APC 12 x 6 pusher, so the motor should have no difficulty at all turning that prop. I have turned much larger with the same motor. The ESC was an Ice 50, so again there should not have been any issues with respect to load being drawn. The defective transistor seems the most plausible theory right now.
I will go over the installation with a fine toothed comb before we risk another ESC. If I remember correctly, the ESC was mounted fairly tight up against the fuselage, so I will recommend the owner stands it off a bit next time so that cooling air can reach both sides of the ESC!
Cheers H^^
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I've heard a lot of guys having problem with the Ice Lite 50.
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How so Randy? Both Alan and I used the Ice Lite 50's in our original electric ships with no issues (once Will Hubin sorted out my software version issue).
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I just hear a lot of guys saying the went haywire (pardon the pun). Seems weird is all. Others say they work fine.
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Hi all
This allows me to kill two birds with one shot.
This test stand I made up about 4 years ago. I can set up any motor
by making mounts that fits a universal pattern. There is the Watts up meter
What you see now is Igor's ESC/Timer setup (Just came in the other day)
I only run it long enough in this case to check rotation and delay. Thanks Igor everything works
fine. Now I get to put it in my Infinity and try it out this weekend. %^
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There must be a hole behind the motor for proper cooling.
Regards
JCP
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Hi all
This allows me to kill two birds with one shot.
This test stand I made up about 4 years ago. I can set up any motor
by making mounts that fits a universal pattern. There is the Watts up meter
What you see now is Igor's ESC/Timer setup (Just came in the other day)
I only run it long enough in this case to check rotation and delay. Thanks Igor everything works
fine. Now I get to put it in my Infinity and try it out this weekend. %^
What is that ribbon you have taped to the bench top for? I also saw it on the bottom of your plane in the other thread??
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Thanks for the response Igor. I suspect it may have been a defective ESC. The motor is an E-Flite 25, with an APC 12 x 6 pusher, so the motor should have no difficulty at all turning that prop. I have turned much larger with the same motor. The ESC was an Ice 50, so again there should not have been any issues with respect to load being drawn. The defective transistor seems the most plausible theory right now.
I will go over the installation with a fine toothed comb before we risk another ESC. If I remember correctly, the ESC was mounted fairly tight up against the fuselage, so I will recommend the owner stands it off a bit next time so that cooling air can reach both sides of the ESC!
Cheers H^^
Chris,
I had my Electra jet profile set up with Hacker A30, and Castle Ice Lite 50 13x4.5,, the ESC went poof in a cloud of really nasty smelling smoke in flight at the bottom of a loop, so low load, it just decided it was done. This ESC had already made several flights on this exact combo before taking a dump,, so I am not using the 50 anymore, having moved up to the 75,, ( not for current carrying , just because I have heard of the 50's having issues)
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What is that ribbon you have taped to the bench top for? I also saw it on the bottom of your plane in the other thread??
Doug
The ribbons are the wires for the timer/accelerometer The ribbon wasn't taped to the bench it was just attached as part of the system to run briefly mostly to make sure the rotation and delay is correct.
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I've heard a lot of guys having problem with the Ice Lite 50.
I talked to one of those guys (Tom Strom????) who was having fits with his. He ended up sending some back to Castle. What Castle told him was that there were lots of little solder balls all over the board. This (according to me) was a manufacturing problem -- somewhere in the soldering and cleaning process, lots of little solder balls were left on the PC board (PC board soldering these days is done by laying down a paste of flux and little solder balls, sticking the components onto the paste, then running the whole thing through an oven to melt the solder -- the balls were probably from a combination of paste application and poor cleanup). This would have caused lots of randomly-occurring short circuits throughout the board; all it would take would be transistor A turning on when transistor B should have, or the microprocessor getting confused about commutation, and the board would go PFFFFT!
Such problems don't say anything about the design of the board, one way or another, and it was probably isolated to one particular production run or maybe even some set of boards within that run.