diff --git a/README.md b/README.md index 16befa4b098457aca4797270ed1ab31587d82e71..7fd9c9368b227087b5850d3dfcb24a29c978964f 100644 --- a/README.md +++ b/README.md @@ -1,5 +1,16 @@ # Dynamometer +## Week 5 - 4/1/21 + +This week I took a first stab at one of the initial motivations for building the dynamometer, but that I've neglected so far. That is looking at stepper motor torque limits as we approach saturation and thermal limits for the motor. The plot below illustrates this by sweeping through increasing current chopping setpoints (remember that open loop stepper motors are driven as constant current devices). What we see is a surprisingly linear response in peak holding torque (keep in mind these tests are conducted at 0 rpm). + + + + +[Here's a link to the stepper that I am testing.](https://www.omc-stepperonline.com/nema-23-bipolar-1-8deg-1-9nm-269oz-in-2-8a-3-2v-57x57x76mm-4-wires.html) It's one of the more commonly used NEMA23 steppers used for DIY applications, rated for 1.9Nm at 2800mA. Fortunately this lines up extremelyt well with our own tests! At 2500mA we acheive a peak torque of 195N*cm. Below is an image of stepperonline's speed torque curve (you can disregard the 36V vs 48V difference as this has minimal impact at 0 RPM). + + + ## Week 4 - 3/25/21 This week I focused on improving data analysis (see the nicely interpolated speed-torque curves below), speeding up test times, and slogging through the endless process of finding bugs and improving repeatability. diff --git a/images/dyno/23HS30_2804S.png b/images/dyno/23HS30_2804S.png new file mode 100644 index 0000000000000000000000000000000000000000..938d9acf0f689d527460a0daebcb3e42aaa75c74 Binary files /dev/null and b/images/dyno/23HS30_2804S.png differ diff --git a/images/dyno/currentSweep.png b/images/dyno/currentSweep.png new file mode 100644 index 0000000000000000000000000000000000000000..704fc4c8bbab3e02acb5c070288e4b03d59b0280 Binary files /dev/null and b/images/dyno/currentSweep.png differ