# paper: Simple Motor Calculator

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Simple Motor Calculator
by: Ether

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MCALC17b Jan28 2017 Beta 2102

2x 3x 4x CIM & 775Pro spec files here

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MCALC32ab.zip (31.3 KB)
MCALC32.PDF (63.8 KB)
MCALC32ae.zip (30 KB)
MCALC_2013a.zip (30.2 KB)
MCALC_2013b.zip (30.3 KB)
MCALC_2014c.zip (31.1 KB)
MCALC_2014d.zip (31.2 KB)
MCALC17b.zip (37.1 KB)
2x 3x 4x CIM & 775Pro.zip (1.26 KB)
CIM MINI 775Pro multiple motors.zip (3.34 KB)

Simple Motor Calculator

I created this small app for my own use, then realized that others might find it interesting/fun/handy.

Constructive criticism and error reports welcome.

Note: for those looking for something more comprehensive, check out JVN’s calculator.

http://www.chiefdelphi.com/media/papers/2059

**

The updated version will allow you to enter a desired motor power, and it will then calculate the rpm range, the torque range, and the current range over which the motor will deliver at least that much power.

Also, if there is some reason why you want to always operate the motor at or above a certain efficiency, you can enter the desired efficiency and it will calculate the rpm range, the torque range, the current range over which the motor will operate at an efficiency equal to or greater than the entered number.

**

Ether, nice little program and simple to use. great work. As an Engineer, I am always impressed at what people come up with to solve simple problems when the use the theory of “STICK ON A STRING”. If you keep this in mind when face with a problem, life will be great and a little less stressful.

Again, Do not stop what it is that you do best, GREAT WORK.

*I have updated the motor calculator for the 9015 (am-0912) and PG71 (am-0914) 2012 motors.

The app is now 32-bit so it should now run in 64-bit Windows (XP & 7).

I am re-working the floating-point error trapping and will update again when that is done.

Enjoy.

Works in 32-bit or 64-bit Windows.

Scrollable window.

Includes 9015 (am-0912), PG71 (am-0914), and fc12-20 motors.

As soon as this is settled, I will update the calculator.

Sorry for any inconvenience.

*Motor Calculator build MCALC32g 1/9/2012 350p

Now supports the following motors:

CIM

FP0673
FP2719
FP9012
FP9015

RS395
RS540 (not legal for 2012 but included)
RS550
RS775-12
RS775-18

am-0912
am-0914

DensoL
DensoR
Denso AE235100-0160

*Here’s a copy-and-paste ticker tape output from the motor calculator. If you disagree with any of the specs please let me know. Thanks:

``````Motor Calculator  build MCALC32h 1/9/2012 643p

CIM FR801 001, AM802 001A @ 12.00 volts:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
0.0   0.000    5310   100.0     2.7         0.0        32.4     0.0
@ stall:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
343.4   2.425       0     0.0   133.0         0.0      1596.0     0.0
@ max power:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
171.7   1.212    2655    50.0    67.8       337.1       814.2    41.4
@ max efficiency:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
42.8   0.302    4648    87.5    18.9       147.1       227.3    64.7

FP 00801-0673 @ 12.00 volts:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
0.0   0.000   20770   100.0     0.8         0.0         9.8     0.0
@ stall:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
75.4   0.532       0     0.0   108.7         0.0      1304.4     0.0
@ max power:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
37.7   0.266   10385    50.0    54.8       289.5       657.1    44.1
@ max efficiency:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
6.0   0.043   19110    92.0     9.4        85.2       113.3    75.2

FP 000968-2719 @ 12.00 volts:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
0.0   0.000   16100   100.0     2.0         0.0        24.0     0.0
@ stall:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
57.5   0.406       0     0.0    63.0         0.0       756.0     0.0
@ max power:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
28.8   0.203    8050    50.0    32.5       171.1       390.0    43.9
@ max efficiency:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
8.7   0.061   13665    84.9    11.2        87.9       134.7    65.2

FP 000968-9012 @ 12.00 volts:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
0.0   0.000   15600   100.0     1.0         0.0        12.0     0.0
@ stall:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
59.5   0.420       0     0.0    63.5         0.0       762.0     0.0
@ max power:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
29.8   0.210    7800    50.0    32.3       171.6       387.0    44.3
@ max efficiency:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
6.6   0.047   13861    88.9     8.0        68.0        95.6    71.1

FP 000968-9015 @ 12.00 volts:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
0.0   0.000   15600   100.0     1.3         0.0        15.0     0.0
@ stall:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
63.7   0.450       0     0.0    70.0         0.0       840.0     0.0
@ max power:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
31.9   0.225    7800    50.0    35.6       183.7       427.5    43.0
@ max efficiency:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
7.5   0.053   13761    88.2     9.4        76.4       112.3    68.1

M3-RS395-12 @ 12.00 volts:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
0.0   0.000   15500   100.0     0.5         0.0         6.0     0.0
@ stall:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
16.7   0.118       0     0.0    15.0         0.0       180.0     0.0
@ max power:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
8.3   0.059    7750    50.0     7.8        47.8        93.0    51.3
@ max efficiency:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
2.6   0.018   13107    84.6     2.7        24.9        32.9    75.9

***NOTE*** RS540 is not legal for 2012

RS540 @ 12.00 volts:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
0.0   0.000   17200   100.0     0.9         0.0        11.2     0.0
@ stall:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
32.6   0.230       0     0.0    36.8         0.0       441.6     0.0
@ max power:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
16.3   0.115    8600    50.0    18.9       103.8       226.4    45.8
@ max efficiency:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
4.5   0.032   14841    86.3     5.8        49.1        70.2    70.0

RS550 stall torque changed to 70.5 oz-in per 2012 FRC specs

M5-RS550-12 (-B) @ 12.00 volts:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
0.0   0.000   19300   100.0     1.4         0.0        16.8     0.0
@ stall:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
70.5   0.498       0     0.0    85.0         0.0      1020.0     0.0
@ max power:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
35.3   0.249    9650    50.0    43.2       251.5       518.4    48.5
@ max efficiency:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
8.0   0.057   17105    88.6    10.9       101.4       130.9    77.5

M7-RS775-12 @ 12.00 volts:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
0.0   0.000    7300   100.0     1.1         0.0        13.2     0.0
@ stall:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
61.1   0.431       0     0.0    30.0         0.0       360.0     0.0
@ max power:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
30.6   0.216    3650    50.0    15.6        82.5       186.6    44.2
@ max efficiency:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
9.8   0.069    6127    83.9     5.7        44.5        68.9    64.5

M7-RS775-18 @ 12.00 volts:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
0.0   0.000   13000   100.0     1.8         0.0        21.6     0.0
@ stall:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
112.8   0.797       0     0.0    86.7         0.0      1040.4     0.0
@ max power:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
56.4   0.398    6500    50.0    44.3       271.2       531.0    51.1
@ max efficiency:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
14.2   0.100   11363    87.4    12.5       119.4       149.9    79.7

am-0912 (CCL 9015) @ 12.00 volts:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
0.0   0.000   16000   100.0     1.2         0.0        14.4     0.0
@ stall:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
60.6   0.428       0     0.0    63.8         0.0       765.6     0.0
@ max power:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
30.3   0.214    8000    50.0    32.5       179.4       390.0    46.0
@ max efficiency:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
7.3   0.052   14070    87.9     8.8        76.1       105.0    72.5

Specs for am-0914 (PG71) motor are disputed.
Update will be posted when available.

am-0914 (PG71) @ 12.00 volts:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
0.0   0.000      84   100.0     1.3         0.0        15.6     0.0
@ stall:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
4140.0  29.235       0     0.0    26.8         0.0       321.8     0.0
@ max power:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
2070.0  14.617      42    50.0    14.1        64.3       168.7    38.1
@ max efficiency:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
739.3   5.221      69    82.1     5.9        37.7        70.3    53.7

DensoL 262100-3040 @ 12.00 volts:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
0.0   0.000      84   100.0     1.8         0.0        21.6     0.0
@ stall:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
1501.1  10.600       0     0.0    21.0         0.0       252.0     0.0
@ max power:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
750.5   5.300      42    50.0    11.4        23.3       136.8    17.0
@ max efficiency:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
339.5   2.398      65    77.4     6.1        16.3        73.7    22.1

DensoR 262100-3030 @ 12.00 volts:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
0.0   0.000      84   100.0     1.8         0.0        21.6     0.0
@ stall:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
1501.1  10.600       0     0.0    18.6         0.0       223.2     0.0
@ max power:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
750.5   5.300      42    50.0    10.2        23.3       122.4    19.0
@ max efficiency:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
357.4   2.524      64    76.2     5.8        16.9        69.6    24.3

Denso AE235100-0160 @ 12.00 volts:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
0.0   0.000    5300   100.0     1.0         0.0        12.0     0.0
@ stall:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
18.4   0.130       0     0.0     7.0         0.0        84.0     0.0
@ max power:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
9.2   0.065    2650    50.0     4.0        18.0        48.0    37.6
@ max efficiency:
oz-in      Nm     rpm    rpm%    amps   watts out    watts in    eff%
5.0   0.036    3846    72.6     2.6        14.4        31.8    45.2
``````

*[strike]I’ve just been informed (by someone in a position to know) that the “9013” in the KoP Checklist is an error: It should be 9012.[/strike]

Team Update #2 (2012-01-13) added FP-9012 to [R48] and kept FP-9013.

The motor calculator supports the FP-9012. As soon as specs for FP-9013 become available I will add them to the calculator.

*The motor calculator has been updated with the latest (1/16/2012) lab data for the am-0914 gearmotor.

I decided to incorporate 2 separate sets of motor specs for this gearmotor:

one for brand-new (unused) gearmotor, and

one for used (broken-in) gearmotor

… since the lab data indicated a significant difference.

** ACTUAL GEARMOTOR PERFORMANCE PROBABLY LIES SOMEWHERE BETWEEN **

Links to the 3 lab report PDF documents can be found at the bottom of this web page.

If you have even a passing interest in motor testing, you will find this interesting reading.

DOES ANYONE HAVE SPECS FOR THE FISHER-PRICE FP-000968-9013 ???

*Motor calculator has been updated to MCALC32t and includes:

The calculator now gives the user the option to select which specs to use for am-0914, since there are 3 different sets of specs (explained in the am-0914 options menu).
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*MCALC32w fixes a problem with the spec options menu for the am-0914.
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EDIT: MCALC32ab adds exception handling to user-defined motor input
*
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WOW!!! How did you do this? I have been looking for a graph of the information so I could get the general values, but this is far better!

If you assume that the speed vs torque and the current vs torque “curves” are straight lines (which is the standard assumption for almost all the motors used in FRC

), then most of the equations are fairly straightforward to solve explicitly.

For example, at the rated voltage and for a given torque tau, you can find the speed as follows:

speed = free_speed*(1-tau/stall_tau)

some of the other calculations, for example solving for efficiency or finding voltage when given rpm and torque, are a bit trickier, but not too bad.

*
*

Ether == Awesome - any chance you’ll part with the source so I can compile a Linux version?

TIA

It would be good to have a Linux version.

I’ll pull out the formulas and post them.

Give me a couple of days.

If it was a windows console app, it will probably just compile and run quickly with minor changes. You can send the source if you want.

Here ya go.
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