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04-24-2016 05:41 AM  4 years ago
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flycatch

rrApprentice

Barstow, California

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Low Motor RPMs
I'm new to electrics and need some help solving a problem. I recently assembled and Align 550e V1. The kit came with all stock Align components that included a Align 600MX 1220KV motor and a Align 70amp ESC. I calibrated the Align ESC according to the instruction and on the bench it worked. I took it out for a test flight and only managed to get 6" off the ground at full throttle. Both the throttle and pitch curves are five point and again I set them in accordance with the provided manual.
I thought the motor was defective and replaced it with an identical 600MX. I ran it up and noticed a slight difference in rpms from the first one. Test flight was the same as before. Not the motor perhaps it is the ESC and I purchased another with the same results.
So, what do I do now go back to nitro machines and leave electrics for the teck savvy?
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04-24-2016 12:48 PM  4 years ago
Pistol Pete

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Seffner, FL

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Help us help you
Post throtle curves;

ESC settings;

Pinion size;

* Batt specs. (New or Used?)
~~Enjoying the hobby one flight at a time~~
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04-24-2016 04:25 PM  4 years ago
Rojoalfa

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Punta de Mata, Monagas-Venezuela

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Motor is always controled by ESC.
The way you program the ESC, that the way the motor behaved or misbehaved...

Low rpm means low input in throttle...

/
Saludos cordiales,
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04-24-2016 04:30 PM  4 years ago
flycatch

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Barstow, California

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The throttle was calibrated for low/high stick input.
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04-24-2016 04:51 PM  4 years ago
Rojoalfa

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Very good. That the first thing to do, calibration.
You teach your ESC where minimus a maximus are.

Now, your throttle curve.
0, 40, 80, 80, 80

That means, rule of thumb, you are doing 80% of max speed on a flat curve after 50% of throttle position.

0, 25, 50, 50, 50

You are doing 50% of max speed on a flat curve after 50% of throttle position.

Max speed = rpm max= Kv * volts * Tp / Tg

Kv, kv motor.
Volts, your system pack volts nominal.
Tp, amount of pinion teeths.
Tg, amount of gear teeths.

Efficience not in consideration by now...

You did that calculations?

/
Saludos cordiales,
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04-26-2016 07:02 PM  4 years ago
Rojoalfa

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BTW, Align manual is wrong.

Throttle curves are not the Same in electric and nitro.

Electric motors have a constant torque output, so you just need a flat throttle curve.
That means that rpm are not related to pith curve in electric.
That is why electric devices dont need a gear box to compensated torque.

Ok... So... The other problem you may have is a programing issues on ESC. Helis and planes programing are different.

/
Saludos cordiales,
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04-26-2016 08:00 PM  4 years ago
flycatch

rrApprentice

Barstow, California

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What if I told I confirmed low RPMs using a linear throttle curve. I have tried two different brands of ESCs and they are both are performing the same. I have another ESC that I'm using in an electric glider. I configured the ESC using a the trainer button on the transmitter. I mixed this channel into a aux channel and set up the travel to +/- 100 and I'm getting full WOT. I'm not getting the same result using 0-100 percent linear throttle curve. For some unknown reason the esc is not seeing the same thing as the aux channel. I tried a JR 9303 helicopter transmitter and got the same result.
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04-26-2016 10:21 PM  4 years ago
flycatch

rrApprentice

Barstow, California

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Gentlemen I found the problem. Not the; transmitter, esc or receiver. The problem was the stock Align 600MX 1220kv out-runner motor. Today I received a Gartt motor with the same specification of the Align. I installed it, ran it up to WOT and all is well. RPMs increased by 100% with no vibrations. All that is left is the maiden so I can tack it and dial in the numbers. All this time I have been chasing rainbows. When I started this investigation I thought of four things that may cause this problem. Those things were; esc, receiver, motor and transmitter. It took over two weeks to get a new motor from China but it was well worth the wait. For those who reached out to give me advice I thank you but you were looking at the obvious culprits. Who would have thought the motor was the problem.
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04-27-2016 09:18 PM  4 years ago
Rojoalfa

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Punta de Mata, Monagas-Venezuela

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Very Good.

There is a posibility that motor is a 510 Kv.

Not necessary is garbage...

/
Saludos cordiales,
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04-27-2016 10:51 PM  4 years ago
flycatch

rrApprentice

Barstow, California

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You might be on to something. Is there any way that can be confirmed?
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04-28-2016 02:52 AM  4 years ago
Rojoalfa

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Punta de Mata, Monagas-Venezuela

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Following ecuation

Rpm max = Kv * volts * Tp / Tg

Assuming Tg / Tp = 1

Rpm max = Kv * volts

Then

Kv = rpm max / volts

On your test bench, drive the motor with a proper esc at 100% with a pack fully charged. Using a tachmeter read rpm max.

Do the calculations for Kv, dividing rpm max with pack voltage.

Now... Surprise...

/
Saludos cordiales,
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04-28-2016 03:07 AM  4 years ago
ICUR1-2

rrElite Veteran

Ottawa, Ontario

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You might be on to something. Is there any way that can be confirmed?
you'll need a tachometer and a voltmeter >
motor rpm @ WOT divided by volts
spending time, paying attention
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04-28-2016 03:25 AM  4 years ago
Rojoalfa

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Punta de Mata, Monagas-Venezuela

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600MX 1220 Kv and 600MX 510 Kv have identical dimensions.
45 mm diameter and 59 mm long...

There is a chance that has the wrong fan.

/
Saludos cordiales,
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