|Dec 08, 2011, 02:02 AM|
in v345, my SII 3020-1110 is listed with imax of 50 amps. the specs @ inno8 list 60 amps cont. max.
the s 3032-8 (v1) that's on clearance is listed in v345 with an imax of 70. the first chart @ inno8 list it as 90 amps cont. and the second link list it with 114 max cont.
ASS-U-MEENG that the 90 (not 114)is correct is the difference in scorpion calc and the listed values a "buffer" or idiot-zone or do i suffer from the forest/tree syndrome? i didn't check any other imax values, perhaps i should have before i came crying over here.
btw - nice application regardless
michael clyde dupuy
Late Breaking News ---- i thought maybe i needed v346 but, same values as v345.
|Dec 08, 2011, 06:04 AM|
The problem of specifications Max current, Max power, Continuous, Burst is a very complicated problem.
The basic principles is that motor could suffer two dangers :
a) Temperature rising
Depends of V, I (loading by prop and rpm, static or in flight) & running time
Depends also of installation or cooling, environment in the plane
+ throttle management
Dissipated heat corresponds to
** Ohmic losses depending of Rm I^2 (but Rm is depending of temperature)
** Iron losses (+ a very small friction loss) depending of rpm
That energy has to be removed and the resulting temperature rising depends of all the thermal parameters (ambient, thermal capacity, thermal time constant ..)
b) Mechanical overspeed
Overspeed could arrive if you rise the voltage too much
Danger of unbalance vibrations , ball bearings load, rotor scrapping the lams, ....
So consider Scorpion or Innov8tive specs AND Scorpion Calc info like an order of magnitude. It is the responsibility of the hobbyist to get a wattmeter + temp. gun (or a good calibrated finger) and to test motor + batt + prop for some time
(depending if it is a plane, a glider, an heli ...)
It is myself who have decreased in SC (for some Scorpion motors) the Imax, because I am rather conservative.
I am not willing (or risking) to destroy my Scorpion samples on my bench.
Though they are very robust.
|Dec 08, 2011, 07:49 AM|
i understand 100%. it's that very reason i have a 100 amp capable w/meter and i/r temp gun. i even bought an arbor press just because i now own scorpions and can't afford to replace them. no more deep socket and framing hammer shaft removal techniques.
thank you for the prompt and detailed answer. i should have realized it was just some "idiot-proofing" on your part so the "hobbidiot" (meaning me) doesn't destroy a good thing.
always a pleasure to read your post,
|Dec 08, 2011, 12:39 PM|
new Scorpion Calc v3.47
News in SC version 3.47 (see post#1 this thread):
New series HK 3226-900 , HK 3226-1400 ,HK 3226-1600
Zip file size passes from 2.46 Mb upto 2.57 Mb, mainly due to 3 more pictures
Don't forget to select your preferences (imperial or metric units)
When downloading you get the standard .ini (standard preferences)
Scorpion.ini can store your own choices at the first use (when quitting)
|Dec 08, 2011, 05:23 PM|
Central Lake, Michigan
Joined Dec 2002
Louis, I downloaded the latest version 2.46 yesterday onto a thumbdrive as I had to download at the local library as I do not have high speed..only dial up. When I loaded the program into my computer and after going through all the set up steps, the program would not run unless I kept the thumbdrive plugged in the USB port. What did I do wrong? I deleted the program in order to try it again.
Any suggestions? Using Windows XP home version.
|Dec 08, 2011, 06:21 PM|
Last version is v3.47 !!
Generally there is no problem, if you download the zip
Then copy the zip in your SC folder or any
You have to get 3 files in the same folder
Readmefirst.txt (to read)
.exe and .ini
|Dec 08, 2011, 07:45 PM|
copy the scorpion zip file to your comp. desktop before you unpack it. depending which app you use for .zip files you may need to make a folder for it first (as fourdan stated) before unpacking it. before you unpack it, after copying from your flash drive, be sure and remove the flash drive. sometimes xp will geek like that, especially without service pack 3 installed.
NOTE: there was no version 246, it went from v232 to v301 so i guess you meant v346 which fourdan updated to v347.
|Dec 08, 2011, 11:52 PM|
Central Lake, Michigan
Joined Dec 2002
I forgot to mention this computer does not have any previous SC in it. I'm starting clean here and have attempted to reinstall with your suggestions without success but I really don't know what I'm doing either. My computer knowledge is quite limited so I'm going to need some detailed instructions.
I managed to load it with Install Wizard after installing to desktop but still won't work without the flash drive. I'm missing something here.
|Dec 10, 2011, 06:03 AM|
The best could be that you find a good friend with some PC science.
No need any wizard installer prog.
Unzip the zipped file to get 3 files (.exe .ini .txt)
Then copy in one folder (any for example ...../Scorpion Calc/)
Important is to have .exe AND .ini files in the SAME folder
Readmefirst.txt is just info
To uninstall just delete the folder (nothing in Windows registers)
|Dec 29, 2011, 01:21 AM|
Joined Dec 2011
A few curious questions
Hi fourdan thank you for providing this program, it is really very comprehensive, i'm impressed by the flexibility it offers.
I've got a couple of curious questions that i haven't been able to find answers for, if you could give me an idea that would put my mind to rest!
1. i've got the 4025-630 motor, and when i put motor-on-time as 10min, the temp graph shows 150deg is only reached at 115A at 12s - i.e. about 6kW. but the specification in the program is only 60A/1min. which one should i trust more? i understand that the graph is based on ambient 20deg.
2. the 4025-630 has a lower winding resistance than 550, yet has a lower rated Imax, which i cant explain. the calculations suggest a higher Imax
3. for the esc resistance, is that the sum of all three phases? i'm asking because the default values seem very high. e.g. my 100A esc has a max 1.5mohm per phase in fet resistance, at max temp. the wires contribute at most another 1mohm. the default value on the calculator however is 6mohm.
4. this one has bugged me for the longest. of all the 40+mm motors in the scorp family, they all use tapered fan, why is that? i found them to generate very little airflow. the 2221 motor i have has the straight cut fan, and cools down exceptionally fast. was it an efficiency decision? how much motor efficiency do you gain from the tapered fan?
I'm looking forward to hearing back.
|Dec 29, 2011, 06:56 AM|
(but I know Georges VG and met him several times when I visit my son's family living in HongKong)
In exchange I receive generally (95%) one free sample of Scorpion motors to test-review.
Your questions are not curious.
a) There is a temperature 3D distribution (with temperature inside gradients)
b) Starting from ambient cooling air, there is a curved-slope going to an asymptotic temp. limit when the balance 'heat generated (Wd dissipated watts) = heat extracted' is reached.
Wd has two parts Ohmic losses and Iron losses.
It is interesting to run (IF POSSIBLE) with some high voltage in order to have equality between ohmic and iron losses (Peakeff)
c) The asymptotic temp. is a function of some °C/Wd depending of both motor parameters and air cooling
Motor parameters are depending of volume, mass and design.
d) The starting slope is a function of thermal constant (in minutes) also function of the motor and environment
Scorpion Calc is calculating with a TYPICAL set of all those effects. The best final judge is the real world measurement with an IR gun (map or fixed beam).
Consider thermal analysis of SC like a "ball park indicator" or to compare roughly 2 motors
HK4025-630 Imax 65A Pmax 2700W
HK4025-550 Imax 65A/(85A 5seconds) Pmax 2450W 5 seconds
I think I will update indicators HK4025-550 to 60A and HK4025-630 to 65A
So internal resistance (ON) is generally given as 2xRdson. That value is depending
a) of the performance of MOSFETs (recent devices and some brands are better than old devices)
b) of the max amperage
c) of the max voltage
Generally ESC manufacturers are not indicating internal resistance.
MGM is indicating for Xseries (recent MOSFETs)
60A 26V 2x0.8 mohm
120A 26V 2x0.4 mohm
160A 26V 2x0.35 mohm
280A 26V 2x0.18 mohm
62A 45V 2x1.0 mohm
125A 45V 2x0.5 mohm
140A 35V 2x0.55 mohm
140A 63V 2x0.33 mohm
Probably chinese cheap ESC are not using the same quality MOSFETs and internal resistance is higher
You have to add cables and connectors internal resistance from the battery to the motors (typically several mohm more)
|Jan 09, 2012, 02:03 PM|
New version Scorpion Calc v3.48
Please use new Scorpion Calc version v3.48
Please delete your old versions .. 3.47
It appears that some thermal coefficients °C/W and thermal time constant
were damaged in the data base (only some S 22xx motors).
That erroneous coefficients were disturbing the results (too much rising temperature)
|Mar 12, 2012, 07:00 PM|
Joined Aug 2011
Issues and added features...
I have been using Scorpion Calc for a while and have started using the generic prop feature. I have discovered a minor issue. When the K2(thrust) box is updated it does not change the calculated thrust until the focus is shifted to another box. i.e. you have to click and some other box before it will update the thrust data. This is very annoying and leads to errors if you forget. I have done this many times and rendered long strings of calculations worthless due to this simple error.
It would also be very nice if there was some method of saving the propeller data in a file. When trying a large number of propellers that are not in the programs internal database I find that I have to keep a large quantity of data in front of me as I cannot remember all the coefficients for all the different propellers. Entering this data manually every time I change the propeller is time consuming, because I have to look up the appropriate coefficients. Its also error prone since they must be manually entered every time. Since I am constantly changing propellers this is a problem.
It would be nice to be able to create a plain text propeller file with the Manufacturer, propeller name, type, maximum rpm, diameter, blade pitch, number of blades, Kp, Kt, and the rpm range for which these constants are valid. Using an APC 20X8E as an example the file might contain the following three lines:
This would allow an individual to create his own prop file with data for many props and solves the problem of trying to find a single set of coefficients to match the entire rpm range of the prop. The reason I believe that a single set of coefficients is not sufficient is the following graph of the Ct, and Cp of a R/C propeller. Notice the changes in the Cp and Ct with RPM. Trying to simulate either of these with a single coefficient would lead to large errors in calculated values or very complicated equations in the program. Neither seems very appealing!