Hello everyone,
I am using T-motor and alpha series ESC in my octocopter frame with following parameters
MOT_PWM_MIN 1100
MOT_PWM _MAX 2000
MOT_THST_EXPO 0.25
MOT_SPIN_ARM 0.07
MOT_SPIN_MIN 0.1
According to t-motor datasheet it will required 50 % throttle to take-off with my AUW frame so PWM should be 1500 to 1550. But its going more than 1660 initially.
Waiting for your response @xfacta @Michael_Oborne @amilcarlucas @Brodo @dkemxr
Please contact T-Motor.
If the copter does not take-off with 1500, then there is nothing the software can do about it, it must apply higher PWM
what motor and esc are you using? The alpha series must have matching firmware loaded to work correctly.
A list of the weight and components such as motor, esc, propp, battery etc would be great
U13 II with 30 inch propeller
& Alpha 24S ESC
first, the throttle position range according to the specs over at T-motors page is 1100-1900. You mentioned you used 1100-2000. That shouldn’t cause what you’re seeing now though. But it might cause issues if the drone ever needs to use the upper end of the throttle curve. If you’re really unlucky the ESC might cut throttle when the signal is out of range.
Also, what weight did you fly at when the issue appeared, and is the octocopter a flat one, or a quad frame/coaxial configuration?
So they say. What is the take-off weight and what battery power? Post a log of a take-off and hover.
In your experience, how much loss does a coaxial configuration give you?
If it should hover at 50% throttle (1500pwm) assuming the weight of the craft matches what 8 of these motors would produce according to t-motor, a pwm of 1660 would give a thrust loss of around 32% if I calculate the increase over the used pwm range of the alpha ESC (1100-1900).
Could that value be correct for a coaxial configuration? If so, that could be why it won’t perform according to specs?
MOT_THST_EXPO,0.4
MOT_PWM_MIN,1100
MOT_PWM_MAX,1940
then use MissionPlanner motor test to check and set
MOT_SPIN_ARM and MOT_SPIN_MIN
Regarding the
MOT_PWM_MIN
for the alpha 24s ESC (I assume it’s the 60A since they only have one 24s Alpha ESC on their webbsite)
T-motor says the PWM range is 1100-1900 for some reason.
I know that for the others like the Alpha 60A LV that I use it’s 1100-1940 but for this one it’s different for some reason.
(edit is wrong, I looked at the wrong ESC… Rest abow is correct) Edit… They apparently have two versions. the 24s 60A and the 24s 60A V1.2. The 1.2 has the 1100-1940 as you said. I guess we need to know which 24s ESC is used
no wait… ignore my edit. I looked at the 12s version. The 24s only comes in one verion. With 1100-1900 pwm
no, there is just one correct set of PWM range. Some other non-official T-Motor sites list rubbish
Ha - you might be right - I’ve always specified the range I did above 
I see on the official web site the same as what you see too!
Other model Alpha ESCs say
so who really knows??
For example the flame ESCs used to say they couldnt be calibrated and to use the range I specified, but now they dont specify a PWM range at all, but say to calibrate them ¯_(ツ)_/¯
That’s so strange…
and worrying
Not even T-motor really knows how their ESCs work
I think the 24s is the only one that ends on 1900 instead of 1940
…and that matches with some of the other info we received when different people asked about the thrust expo and received different replies
Really alarming,
They need to get their game together before they lose too much trust.
I’ve always seen them as a great high quality brand for industrial machines, I hope they decide that’s what they really want
What’s going on right now is just not sustainable.
All they need to do is join the Ardupilot partner program and get some real dialog going.
That would be amazing. Don’t they have people on the forums already?
They don’t appear very often. Why not @tmotor-industry ?
I have no idea who this might be. Zero activity
I believe someone from their marketing team is on here as well.
But this might be better suited for another dedicated topic. I don’t want to hijack this one
