Stepper motors with built in PS versus ones without


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Thread: Stepper motors with built in PS versus ones without

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    Default Stepper motors with built in PS versus ones without

    Hi all , I was debating to buy a 4'/4' Saturn router table from FLA . Nate has updated the gantry from aluminum to steel , and I don't doubt the gantry is over 200 pounds .

    I would prefer to assemble my own electronics, and have a concern regarding the stepper drivers . If I went with stepper drivers that don't have internal power supplies , then I could load balance the axis by dedicating one PS to the X and Z axis , then dedicate another PS to the Y axis , which I suspect is going to be using the most current .

    Heres where the question comes in . I'm liking these stepper drivers that have a built in PS , as I thought it would make for a cleaner and simpler install .
    But if I go that route I'll have one dedicated to each axis , and no load balancing. Am I over thinking this ?
    Sorry I forgot to mention I'm going with Nema 34 steppers .

    These are the ones I was going to purchase and buy 10 amp PS's .
    http://www.automationtechnologiesinc...nk-is-included

    But these are the ones I'd like to purchase .
    https://cnc4pc.com/rsd110-6-ac-line-...tml#prodtabs-3

    Similar Threads:
    Last edited by MajorTendonitis; 04-01-2017 at 12:15 PM.


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    Default Re: Stepper motors with built in PS versus ones without

    (Am i overthinking this?) Probably, looks like they will both work fine.



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    Default Re: Stepper motors with built in PS versus ones without

    I just thought you would have more real estate in the enclosure , but I think I'm going to put the kibosh on those and go with two separate 48V power supplies and the first ones I posted .
    I haven't seen anyone on YouTube use this version with the intergrated PS yet .
    ( Not that YouTube is my bible ).
    It may be because there more expensive , even after buying a separate power supplies .
    They may make it harder for future trouble shooting also , and if you need a replacement, then there's the higher expense .
    Buying four of those would certainly add up .

    Thank you for the reply , as I'm just learning and need all the direction I can get

    I don't actually know anything about CNC router tables , but I stayed at a Holiday Inn Express last night


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    Default Re: Stepper motors with built in PS versus ones without

    I did some looking and found some older threads about those drives here. Looks like they've been around for a few years. They're sold by a few different sellers. It would be nice to find out who makes them.

    A 10a power supply will easily power 2 motors, so you only need 2 power supplies for 4 motors.

    Gerry

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    Default Re: Stepper motors with built in PS versus ones without

    Quote Originally Posted by ger21 View Post
    I did some looking and found some older threads about those drives here. Looks like they've been around for a few years. They're sold by a few different sellers. It would be nice to find out who makes them.

    A 10a power supply will easily power 2 motors, so you only need 2 power supplies for 4 motors.
    Thanks for the post .
    Yes , I was going to dedicate one PS to the two steppers on the Y axis , and one to the X and Z axis . My concern was the gantry would be in need of more current demand because of its weight, but as you say , 10 amps should suffice

    I don't actually know anything about CNC router tables , but I stayed at a Holiday Inn Express last night


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    Default Re: Stepper motors with built in PS versus ones without

    Just to make sure I'm not going crazy... there is NO spec on this page:
    https://cnc4pc.com/rsd110-6-ac-line-...tml#prodtabs-3
    for the amperage or wattage being delivered to the steppers... right? They make absolutely no claim for the amount of POWER delivered.

    And, if I read the description correctly, it is NOT a built in power supply at all... They are directly applying 110 volt AC to the motor leads. I base that on this text copied from the page:
    Warning: This device produces lethal electrical current. By purchasing this drive you agree that Rex Machine Industries is not liable for injury or peoperty [sic] damage resulting from use of this drive.
    Application Note: Due to the high voltage applied to the motor's windings, many steppers need to be configured in series as they may overheat in parallel...
    ...
    This is not the case when 110-120VAC is rectified within the drive to 150-160VDC.
    So if you hook this up to a stepper motor rated for e.g. 60 volts, where the motor manufacturer used winding insulation that is rated up to maybe 120 volts, this thing could easily burn the motor out.

    Not to mention electrocute you if you accidentally touch the motor leads.... I guess that's always a possibility, but... damn...

    And no word on how much amperage / power is delivered.

    I'd almost like to see someone try it just to find out if their motors (and themselves) survive!

    James hosts the single best wiki page about motors for CNC hobbyists on the net:
    http://techref.massmind.org/techref/io/motors.htm Disagree? Tell him what's missing! ,o)


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    Default Re: Stepper motors with built in PS versus ones without

    Quote Originally Posted by James Newton View Post
    Just to make sure I'm not going crazy... there is NO spec on this page:
    https://cnc4pc.com/rsd110-6-ac-line-...tml#prodtabs-3
    for the amperage or wattage being delivered to the steppers... right? They make absolutely no claim for the amount of POWER delivered.

    And, if I read the description correctly, it is NOT a built in power supply at all... They are directly applying 110 volt AC to the motor leads. I base that on this text copied from the page:


    So if you hook this up to a stepper motor rated for e.g. 60 volts, where the motor manufacturer used winding insulation that is rated up to maybe 120 volts, this thing could easily burn the motor out.

    Not to mention electrocute you if you accidentally touch the motor leads.... I guess that's always a possibility, but... damn...

    And no word on how much amperage / power is delivered.

    I'd almost like to see someone try it just to find out if their motors (and themselves) survive!
    Thanks James good points . I think it's best I just stay away from those period and go old school

    I don't actually know anything about CNC router tables , but I stayed at a Holiday Inn Express last night


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    Registered jfong's Avatar
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    Default Re: Stepper motors with built in PS versus ones without

    Not sure if I would trust those drivers to be 100% safe to use but they do make industrial stepper drivers that are 110 or 220 AC input. I have a Parker E-AC stepper driver that I use for a rotary axis. AC line input. Pretty expensive drive but I found this one new on eBay for about $50. I don't use the rotary axis all that much so I just plug it in when I need too. Yes you need to be very careful of the motor leads due to the higher voltage. Must use high grade cabling and connectors.



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    Default Re: Stepper motors with built in PS versus ones without

    A few comments.

    Voltage does not burn up the motors, current does. Although the drive linked didn't have specifications listed it is probably the same or similar to this one sold by automation technologies:

    http://www.automationtechnologiesinc...-stepper-drive

    The above drive does have current limiting that is settable via DIP switches, so if working correctly, the current should be limited to prevent burning up the motor.

    I have never seen a stepper motor "rated" for anything near the voltage we drive them at. For example, the largest NEMA 42 stepper sold by Automation Tech is "rated" for only 5.38v. The voltage rating of a stepper is simply the maximum voltage that can be applied and have the motor winding resistance naturally limit the current. The formula for this is I=V/R. That same NEMA 42 is rated for 8 A, 5.38V and has a winding resistance of 0.69 ohms. From this, 5.38 / 0.69 = 7.8 amps. So a voltage of 5.38V cannot exceed the 8 amp limit. The Gecko ideal voltage for this stepper would be 114V based on its inductance of 12.7 mH. Without current limiting, 114V would see 114 / 0.69 = 165 amps, so even at the Gecko recommended, the current needs to be limited. Incidentally, the insulation on that motor is rated to 500V. Even the popular 570 oz-in NEMA 23 has insulation rated to 500V.

    For electrical heating the most common formula used is P = I^2 * R, so since the resistance isn't changing, what determines the electrical heating is I or current. So limiting the current will limit the electrical heating. Now some will say that P = V * R, which is true, but in the case of a chopper drive the output voltage to the stepper motor is not constant since the output is essentially switched on-off-on-off... rapidly to control the current. You would have to use the average voltage, which would mean knowing the duty cycle of the pulsed output. So, you can't use the power supply voltage to calculate the electrical heating. In the 110V drives being discussed the rectified voltage is going to be about 160VDC, but this is not the average voltage going to the motor.



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    Default Re: Stepper motors with built in PS versus ones without

    Thanks again for the posts guys .

    109jb , your a heck of a lot smarter than I'll ever be

    I don't actually know anything about CNC router tables , but I stayed at a Holiday Inn Express last night


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Stepper motors with built in PS versus ones without

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