So I have a bad Z-axis motor, yes I have ensured that it is the motor, and I want to make sure I purchase a compatible motor for easy swapping. My LR2 uses the SKR Pro 1.2 kit bought from the V1 Engineering shop. I know I could just order the Nema KL17H248-15-4A, but I haven’t found any that will get delivered this week and would like to be up and running this weekend. If anyone knows an appropriate alternative please let me know. Thanks Peeps!
Most NEMA17 motors will physically fit onto the machine, and will have an appropriately long 5mm motor shaft. The mounting screws are a part of the NEMA17 specification, so they should all bolt in.
Otherwise, you are looking for a 1.8° full step (200 steps/rotation) and about the 76 oz-in torrque specification, a minimum of about 1.5A current rating. Most will be 4 wire, which is what you want. 6 wire ones can be used, so long as you connect the appropriate 4, but I’d stay away from that.
Having the 4 pin female Dupont connector would be nice, as it’s a direct replacement then, but the JST connector is OK if it’s going directly to the SKR Pro. (Dual endstop configuration.)
Motors with a higher current rating or higher holding torque will not pose a problem at all, while a lower rating might not pose a problem, too much lower and the motor simply won’t be strong enough to ensure that it’s able to lift the lowrider.
There are many examples of 84 os-in torque motors on Amazon, some of which will qualify for next day.
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That’s pretty much what I was thinking, but I was thrown off by the amp rating since the TMC2209 is rated for a 2A drive current with a 2.8A peak. The 5-17HS19-2004S1 is rated at 2A and I wasn’t sure if that would burn out the 2209 driver quickly. What do you think?
No problem there. The driver determines how much current. So long as the motor can withstand the amount of current that the driver is sending, it’ll be fine.
Stock V1 firmware for the SKR is set ot 0.9A, IIRC. In any case, the 2A current rating on the motor wont be a problem.
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Sweet, thank you for saving me a crap ton of time researching all of this information you are Awesome!
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If you decide to adjust the current output of your stepper drivers upward given the motor’s higher torque that, based on the values quoted, it is likely that Dan’s 0.9A value is RMS and the 2.0A for your stepper motor is peak. I’m guessing that 0.9A RMS would be around 1.3A peak.
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