[chbot] Question regarding stepper motors

Mark Atherton markaren1 at xtra.co.nz
Mon Feb 24 03:48:30 GMT 2020


Good enough, I would say that your phase resistance is probably quite 
close to 5.7 ohms.

So next step is to find a stepper with similar weight, dims, and 
resistance and take associated electrical parameters as a starting point 
- maybe the bangood part.

Assume that any given volume of stepper can dissipate similar power. 
Work out what that might be for the bangood unit, then recalculate 
forward using 5.7 ohms to find current etc.

-mark


On 24/02/2020 4:37 PM, Michael Dawson wrote:
> The meter measures 0.00 when I short the probes together, I didn't 
> have a 4.7ohm resister, lowest I had was a 10ohm which the meter read 
> as 10ohm.
>
> Cheers
>
> Michael
>
> On Mon, 24 Feb 2020 at 16:04, Mark Atherton <markaren1 at xtra.co.nz 
> <mailto:markaren1 at xtra.co.nz>> wrote:
>
>     It's notoriously difficult to measure these kind of resistances
>     using the two-wire method, so please double check before going any
>     further.
>
>     Do you have a 4.7 ohm resistor you can read using the same meter,
>     just to verify test meter lead resistance
>
>     or pass a known 200mA thorough the phase (with one meter on
>     current in series), and measure voltage directly across the phase
>     using a second meter.
>
>     -----
>
>     If you can't do either of the above, what resistance do you get
>     when you short the meter's probes together ?
>
>     slowly, slowly ...
>
>     - Mark
>
>
>
>
>     On 24/02/2020 2:42 PM, Michael Dawson wrote:
>>     OK Measuring 5.7 ohms through a phase.
>>
>>     Does this suggest it's not a 1.33A?
>>
>>     Cheers
>>     Michael
>>
>>     On Mon, 24 Feb 2020 at 14:24, Mark Atherton <markaren1 at xtra.co.nz
>>     <mailto:markaren1 at xtra.co.nz>> wrote:
>>
>>         So, a bit like https://www.banggood.com/search/990669.html
>>
>>         Looks like the standard length is 34mm, colours may be
>>         standard, and weight is 220g. Allowing 12g for your gear,
>>         this all sounds very similar..
>>
>>         Your part number is D42HSC1413B-24, so it looks like the D42
>>         part could be associated with faceplate size.
>>
>>         googling "d42hsc" stepper motor indicates that d42hsc may be
>>         the family of the part you are looking for.
>>
>>         The DC resistance of the Bangood part above is 2.1ohms per phase.
>>
>>         If you can measure low resistances with accuracy, see what
>>         your resistance is for one phase. Or pass 200mA through a
>>         phase and measure volt drop.
>>
>>         -Mark
>>
>>
>>
>>
>>
>>
>>         On 24/02/2020 1:32 PM, Michael Dawson wrote:
>>>         4 wires into a 6 wire plug, colours from left looking
>>>         towards the motor, black, space, red, green, space, blue.
>>>         Dimensions 42mm x 42mm Faceplate x 33mm depth of motor.
>>>         232 grams weight including cog, can weight without that is
>>>         that would help.
>>>
>>>         Cheers
>>>         Michael
>>>
>>>         On Mon, 24 Feb 2020 at 13:06, Mark Atherton
>>>         <markaren1 at xtra.co.nz <mailto:markaren1 at xtra.co.nz>> wrote:
>>>
>>>             Hi Michael,
>>>
>>>             Welcome aboard.
>>>
>>>             A few parameters which may be useful:
>>>
>>>             - How many wires, what colours
>>>
>>>             - Overall dimensions
>>>
>>>             - Weight
>>>
>>>             Regards, Mark
>>>
>>>
>>>
>>>             On 24/02/2020 12:25 PM, Michael Dawson wrote:
>>>             > I am trying to calibrate the A4988 drivers for the
>>>             stepper motors for
>>>             > my laser engraver/cutter, using Arduino Uno and the
>>>             CNC shield,
>>>             > (because the one that came with the cutter was pirated
>>>             software and
>>>             > didn't work how it was supposed to and I want to run
>>>             laserGRBL anyway).
>>>             >
>>>             > The issue I am having is, I have not got the specs for
>>>             the stepper
>>>             > motors and aliexpress did not provide the specs.
>>>             >
>>>             > I think they are nema17, but the only hint I have to
>>>             that is that when
>>>             > I search on the number etched into the motors
>>>             D42HSC141B-24 I find an
>>>             > old banggood ad saying they are nema17 but if you
>>>             click on the link
>>>             > the original ad is long gone.
>>>             >
>>>             > I currently have them set to 0.952v when measured
>>>             connected to the
>>>             > arduino and cnc shield which is what was suggested, if
>>>             they were rated
>>>             > to 1.7A. I'm hoping that is correct for these
>>>             steppers, so I guess my
>>>             > question is does anybody have these same steppers and
>>>             know the specs,
>>>             > or do they know it they are indeed rated to 1.7A
>>>             >
>>>             > Or is there a way to find the Amp rating other than
>>>             the etching on the
>>>             > side of the stepper?
>>>             >
>>>             > Any help would be much appreciated.
>>>             >
>>>             > Oh hi BTW, my name is Michael, one or two of you may
>>>             know me, I ran
>>>             > Red Dwarf BBS back in the day, (I just remembered, I
>>>             had the Red Dwarf
>>>             > logo display in RIP script when you logged in, pity
>>>             that never really
>>>             > took off.)
>>>             >
>>>             > Michael
>>>
>
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