Motors drawing no current

General Discussion
1

Basic Information:

Printer Model: custom awd corexy
MCU / Printerboard: btt octopus pro v1.1
Host / SBC pi4
klippy.log

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Describe your issue:

…

Hi, I’m running into an issue with octopus pro v1.1. For some reason the motors are pulling much less current than expected. I am running a 24V psu for most components, but and I’m using a 48V psu for the x and y motors. I have a multimeter connected in series with the 48V psu to read the current draw of the motors. I am running an awd corexy motion system and set the run_current in klipper to 2A. I expect the current draw to be a total of 8A while the motors are fully loaded but the multimeter is only reading 2ishA. I have the jumpers in the correct place to use motor power. Does anyone know why this is happening?

I tested the motors one by one and each motor was only pulling 0.45A each when they were under heavy load. For heavy load I was using the test speed macro at 500mm/s and 20kmm/s2.

I am running tmc5160 drivers and actively cooling them.

How does run_current work?

Here is a picture of motor spec sheet:

IMG_1137
IMG_11373024×4032 1.48 MB

I know this was a little all over the place but I appreciate the help! Please let me know if I can provide any more info.

2

The klippy.log was requested and it is missing.

Please attach it to your next post

1 Like
3

Hold on I’ll reply with the klippy log thanks

4

klippy (5).log (42.7 KB)

Here’s the klippy log. Thank you

5

So, what version of the TMC5160 do you have: Standard or HV?
Standard is rated up to 35V and HV up to 50V

Also, 2.3A is quite high. Even for steppers rated at 2.1A

Here you can find information on this (3rd section):

https://learn.watterott.com/silentstepstick/faq/

6

I’m using the hv stepper drivers so they can handle the voltage. I’ve made sure to size all components to be able to support the high volt and high amp.

1 Like
7

Does this article also apply for tmc5160s?

8

HV has nothing to do with the current. According to your image, the steppers are rated at 2.1 A, which would give you a max run_current of 1,48 A

9

Sorry, it was to calculate the voltage to set the current on standalone drivers.

10

That’s fine. I’d love to run them with that current. But at the moment each motor isn’t pulling more than 0.6A. How can I get them to pull more amps

11

You cannot. The stepper drivers (TMCs) are current regulators. With microstepping, the current is approximately following a sine wave, so your digital multimeter will never “see” this peak current, in the best case it will measure the RMS current.
The equation of
4 x single currents = max current
is probably equally not the reality, because it only would be true if all steppers follow the exact same sine curve and have their maximum at the same point in time.

12

For a proper analytics I would recommend this:

13

Interesting. So you think that everything is working correctly?