Steppers in Series, voltage x2?

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This topic contains 7 replies, has 3 voices, and was last updated by  Jakob A 2 months, 2 weeks ago.

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  • #37771

    rapapar
    Participant

    Hi,

    I follow that:
    “Series –
    Same amp draw as a single stepper, ideal.”

    I use Ramps 1.4 and DRV8825.

    I use the formula Voltage at the pot=.9*(stepper current/2) to get 1.125V
    I set the three drivers to 1.125V (from GND to POT) without charge (unplugged)
    I get very hot driver quickly when online with the 5steppers, too hot for skin (>60° I think)
    I use simple heaters, glued on chips, exactly the same as here: https://www.vicious1.com/wp-content/uploads/2015/04/labeled.jpg
    As two steppers are in serie, I would take voltage x2. Going to 2.25V. But it is already very hot with 1.125V and it moves smoothly (no tool for now) so…
    Could you please advice me about voltage?

    I will add active fan on the drivers for sure.

    Thanks

    Notice: I use Simplify3D to manually control the moves, it is really nice to see it moving for the first time 🙂

    #37772

    Ryan
    Keymaster
    I use the formula Voltage at the pot=.9*(stepper current/2) to get 1.125V

    Your steppers are 2.5A? we use 76oz/in and they are 1.4A.

    I set the three drivers to 1.125V (from GND to POT) without charge (unplugged)

    You should be setting your drivers while plugged in and powered up (set them about 0.3V low), then energize them buy moving all axis a bit and double check your settings (they will be higher).

    I get very hot driver quickly when online with the 5steppers, too hot for skin (>60° I think)

    The drv8825 can not handle more than 0.7V without heatsinks, any higher than that and you have to have a fan on them at all times, and I find they are not stable above about 1.05-1.1V even with aggressive cooling.

    As two steppers are in serie, I would take voltage x2. Going to 2.25V. But it is already very hot with 1.125V and it moves smoothly (no tool for now) so…
    Could you please advice me about voltage?

    In Parallel you need to *2 the voltage, in series you have to do nothing, that is why we switched to series. More power less heat (slightly lower top speed but we never come anywhere near this limitation).

    Notice: I use Simplify3D to manually control the moves, it is really nice to see it moving for the first time 🙂

    There is nothing wrong with this, but if it is your first time, you really should stick to the way I do things. You can obviously switch at any time but if you have issues we can get you sorted out much much faster if you do things my way. Marlin, reptier host or the LCD, draw my picture, them make your own using estlcam. You would not believe but 90% of the issues are people going out on their own from the beginning. https://www.vicious1.com/assembly/software/

    1 user thanked author for this post.
    #37805

    rapapar
    Participant

    Thanks for your complete answer 🙂

    Your steppers are 2.5A? we use 76oz/in and they are 1.4A.

    Yes, it has very high torque
    Full specs:
    NEMA-17 Bipolar 4-wire
    Step angle: 1.8°
    Holding Torque: 4800g-cm @ 2.5 Amps
    Motor Type Bipolar Stepper
    Manufacturer Part Number 42BYGHW811
    Step Angle 1.8°
    Step Accuracy 5 %
    Holding Torque 4.8 kg·cm
    Rated Torque 4.2 kg·cm
    Maximum Speed (w/1063 Motor Controller) 600 RPM
    Maximum Speed (w/1067 Motor Controller) 4688 RPM
    Acceleration at Max Speed
    (w/1067 Motor Controller) 1.4E+06 1/16 steps/sec²
    Recommended Voltage 12 V DC
    Rated Current 2.5 A
    Coil Resistance 1.3 Ω
    Phase Inductance 1.8 mH
    Shaft Diameter 5 mm
    Mounting Plate Size NEMA – 17
    Weight 332 g
    Number of Leads 4
    Wire Length 300 mm

    The drv8825 can not handle more than 0.7V without heatsinks, any higher than that and you have to have a fan on them at all times, and I find they are not stable above about 1.05-1.1V even with aggressive cooling.

    I’ll check
    With fan it runs 40°C after 15minutes.
    It looks good and can go very fast, but need a check.
    You could watch my video (french language) if you want 🙂

    In Parallel you need to *2 the voltage, in series you have to do nothing, that is why we switched to series. More power less heat (slightly lower top speed but we never come anywhere near this limitation).

    I’m confusing, when I put two 1.5v battery in serie I have 3V. Are you sure? Is it because of internal cabling in motors?

    There is nothing wrong with this, but if it is your first time, you really should stick to the way I do things. You can obviously switch at any time but if you have issues we can get you sorted out much much faster if you do things my way. Marlin, reptier host or the LCD, draw my picture, them make your own using estlcam. You would not believe but 90% of the issues are people going out on their own from the beginning. https://www.vicious1.com/assembly/software/

    Sure, if I get troubles, I will check forum and retry with your advices (great ones!!)

    #37808

    rapapar
    Participant

    Thanks for your complete answer 🙂

    #37809

    rapapar
    Participant
    Your steppers are 2.5A? we use 76oz/in and they are 1.4A.

    Yes, it has very high torque
    Full specs:
    NEMA-17 Bipolar 4-wire
    Step angle: 1.8°
    Holding Torque: 4800g-cm @ 2.5 Amps
    Motor Type Bipolar Stepper
    Manufacturer Part Number 42BYGHW811
    Step Angle 1.8°
    Step Accuracy 5 %
    Holding Torque 4.8 kg·cm
    Rated Torque 4.2 kg·cm
    Maximum Speed (w/1063 Motor Controller) 600 RPM
    Maximum Speed (w/1067 Motor Controller) 4688 RPM
    Acceleration at Max Speed
    (w/1067 Motor Controller) 1.4E+06 1/16 steps/sec²
    Recommended Voltage 12 V DC
    Rated Current 2.5 A
    Coil Resistance 1.3 Ω
    Phase Inductance 1.8 mH
    Shaft Diameter 5 mm
    Mounting Plate Size NEMA – 17
    Weight 332 g
    Number of Leads 4
    Wire Length 300 mm

    The drv8825 can not handle more than 0.7V without heatsinks, any higher than that and you have to have a fan on them at all times, and I find they are not stable above about 1.05-1.1V even with aggressive cooling.

    I’ll check
    With fan it runs 40°C after 15minutes.
    It looks good and can go very fast, but need a check.
    You could watch my video (french language) if you want 🙂

    In Parallel you need to *2 the voltage, in series you have to do nothing, that is why we switched to series. More power less heat (slightly lower top speed but we never come anywhere near this limitation).

    I’m confusing, when I put two 1.5v battery in serie I have 3V. Are you sure? Is it because of internal cabling in motors?

    There is nothing wrong with this, but if it is your first time, you really should stick to the way I do things. You can obviously switch at any time but if you have issues we can get you sorted out much much faster if you do things my way. Marlin, reptier host or the LCD, draw my picture, them make your own using estlcam. You would not believe but 90% of the issues are people going out on their own from the beginning. https://www.vicious1.com/assembly/software/

    Sure, if I get troubles, I will check forum and retry with your advices (great ones!!)

    #37813

    Ryan
    Keymaster
    I’m confusing, when I put two 1.5v battery in serie I have 3V. Are you sure? Is it because of internal cabling in motors?

    We are talking about different things, Amps/volts. Yes the Voltage requirements double be as you can see we are not worried about that. Amps is the limiting factor here, in series the AMP draw is the same.

    There is something fishy about those stepper specs, they are only 66oz/in, we use 76oz/in. The ones you bought are lower torque, use lower voltage but higher amps. The ones we use are low amps higher voltage. The drivers used in this field are amp limited and have voltage in excess, if you buy motors for other projects I would not use the ones you have again.

    #37939

    rapapar
    Participant

    bad news for motors specs but nema17 were hard to find close to France when I buy them. Not so many choices…
    So I’m lucky to have wired them in series
    Maybe I can get other drivers? but it looks like DRV8825 are already the best available VS A4988
    Will see when in charge (with dremel VS ABS) with good voltages…
    THANKS

    #37966

    Jakob A
    Participant

    The steppers are normal enough, its just that they are 42mm long steppers and the ones Ryan is selling are 48mm. (Longer motors are more efficient)
    I think they will work just fine, you probably wont need more power.
    If you want more power anyway, you can buy these (ships from Germany): http://eu.stepperonline.com/3d-printer-nema-17-stepper-motor-59ncm84ozin-2a-17hs192004s1-p-18.html

    1 user thanked author for this post.
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