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Thread: High Power UHU Thread (HP.UHU)

  1. #41
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    Default Re: High Power UHU Thread (HP.UHU)

    Although mine are still sitting in a box as are the motors and hardware I will say thank you for the update but I am bit confused. I have a drawing Revision 1.0c that shows the resistor and diode along with Q5 and a current limit indication LED. R16 goes to +5V instead of the new version going to +15V.

    So why is R16 now to 15V rather than 5V when the op amp is on VCC 5V. And how is the diode a revision for 1.0E when it was already on 1.0C? And why get rid of the Overcurrent LED?

    John Dammeyer

    Last edited by jcdammeyer; 12-17-2014 at 03:41 AM. Reason: additional information


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    Default Re: High Power UHU Thread (HP.UHU)

    Hello;

    The comparator has an open collector transistor output designed for +/- 18Volts, so that is not going to be a problem. The Slow OC circuit charges a capacitor using a current source (approx. 330-k resistor connected to V+), on the old circuit using +5Volts, it works reliably as far as the duty cycle is 100%, but on the UHU derivatives the duty cycle is never 100% so, depending on the duty cycle, the capacitor voltage will be an asymptotic voltage almost never reaching the trigger voltage (3.33V) for the last comparator. With the modification, the integrator voltage will rise almost linearly to the 3.33 Volts and trigger reliably the output comparator and hence the current limiter. Voltage on the capacitor will never exceed 3.33 Volts because as soon as the motor current is turned off, by the limiter circuit, it will start (slowly) to discharge ( 330k resistor will be connected to approx. 0.1volts (Vce (sat))

    Last edited by kreutz; 12-17-2014 at 11:51 AM.


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    Default Re: High Power UHU Thread (HP.UHU)

    The diode/2.2k resistor is a modification on Rev 1.0E because on the Rev 1.0D+ (previous revision) the Slow O.C. current limiter circuit was optional, so the diode and corresponding resistor weren't there. The circuit used only one limiter (fast) (although the schematic also shows the Slow OC but the outputs were tied up). The OC indicator was moved (on REv1.0D+) to the extra Flip flop used to limit the opposite current cycle. If you have an older revision it doesn't matter, you can keep the OC indicator circuit there.

    Last edited by kreutz; 12-17-2014 at 11:52 AM.


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    Default Re: High Power UHU Thread (HP.UHU)

    Is there a link somewhere then to the Schematic Rev 1.0D so I can compare?

    Thanks.



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    Default Re: High Power UHU Thread (HP.UHU)

    On the revision R1.0c pcb the only things to change are the capacitor C28 (to a 2.2uF/25V film capacitor), C29 (to 470pf/50v ceramic) and desolder R16 lead to +5V and wire a cable from +15Vdc to that lead. There were no Rev1.0D+ PCBs sold to the general public, but I know I posted, some time ago, the schematics on one of the many HP-UHU threads here in CNCzone. If you send me a PM with you e-mail address I will send you the schematics, as a reference, but note that they are being superseded by the new Rev1.0E. I don't want to add more confusion to a thread where the HP-UHU information has been already fragmented, for years, into multiple sub-threads.

    kreutz



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    Default Re: High Power UHU Thread (HP.UHU)

    May I ask about irfp4668 and irfp4768 usage ... :

    1. Do I need to change R24, R27, R34 and R31 values and what value do you recommend ?? ( or to keep 22 ohm ?? )
    I need your separate advice for irfp4668 and irfp4768 ...

    2. Can this power stage with irfp4768 run the fanuc type motor ( 47 kg, 36 mm shaft ) , 130 V, 30A ??

    Thank you in advance,

    http://www.bg-cnc.com/wordpress/
    http://www.dailycnc.eu/


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    Default Re: High Power UHU Thread (HP.UHU)

    irfp4668: look at the SOA curve. At 30A the voltage limit is less than 100V. Not good for 130V motor. VR for the diode is specified at 100V.
    irfp4768: The SOA is a little better but at 30A is about 130V, it is not good to work at the limits of the SOA.
    The values of those resistors depend on the total gate charge of the Mosfet and dV/dt required.

    Best regards,

    kreutz



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    Default Re: High Power UHU Thread (HP.UHU)

    Thank you Kreutz,

    For tests with HP-UHU can you recommend me R ( R24, R27, R34 and R31 ) values for 4668 ( 100 V motor ) and for 4768 ( 130 V motor ...) or to use 22 ohm ??

    Regards

    http://www.bg-cnc.com/wordpress/
    http://www.dailycnc.eu/


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    Default Re: High Power UHU Thread (HP.UHU)

    Try 4.7 ohm for starting point. None of those mosfets are good candidates for HP-UHU, If you want to try them is ok, But I am sure they will not be reliable, in the long term, even at 100V.

    kreutz



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    Default Re: High Power UHU Thread (HP.UHU)

    Thank you !

    Can you recommend better mosfets for DC motors - 130 V motor / 30 A for HP-UHU drive ??

    http://www.bg-cnc.com/wordpress/
    http://www.dailycnc.eu/


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    Default Re: High Power UHU Thread (HP.UHU)

    Quote Originally Posted by kreutz View Post
    irfp4668: look at the SOA curve. At 30A the voltage limit is less than 100V. Not good for 130V motor. VR for the diode is specified at 100V.
    irfp4768: The SOA is a little better but at 30A is about 130V, it is not good to work at the limits of the SOA.
    The values of those resistors depend on the total gate charge of the Mosfet and dV/dt required.

    Best regards,

    kreutz
    kreutz, Isn't that SOA showing total wattage in linear mode ?
    IF your MOSFET is conducting 30 amps, i would assume the voltage across the mosfet is 30amps * 0.009 ohms which is 0.27 volts.
    This mosfet seems easily rated to handle a 30 amp motor at 130volts.

    But to drive a Mosfet with that much gate capacitance you would need programmable deadtime. and a lot of drive. And your switching freq would probably need to be about 10khz or lower. , imo

    Larry K

    Manufacturer of CNC routers and Viper Servo Drives
    www.LarkenCNC.com and www.Viperservo.com


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    Default Re: High Power UHU Thread (HP.UHU)

    I've been using the UHU HP servo on my mill and it works perfectly!
    But there are new DC servo motors 20Nm 120V and 400V 34A 11kW.
    Is it possible to improve the UHU HP servo for working with these motors?
    Maybe someone did similar?



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    Default Re: High Power UHU Thread (HP.UHU)

    I've personally tested my HP-UHU with a 160VDC supply and I'm running them with 130VDC (though they haven't been used much to be honest) so your 120V motors should be fine from a voltage standpoint. But how much current do they need? IIRC the inductors on the HP-UHU saturates at around 25A.

    As for running the thing at 400VDC I don't know. I guess you could start by looking at the required creepage distances on the PCB for such voltages, the connectors, the input filter capacitors, the MOSFETs (obviously). Not something I'd recommend.

    /Henrik.



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    Default Re: High Power UHU Thread (HP.UHU)

    Quote Originally Posted by H.O View Post
    But how much current do they need?.
    About 30A.
    I have only this label.
    High Power UHU Thread (HP.UHU)-161020121721-jpg



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    Default Re: High Power UHU Thread (HP.UHU)

    Hi Guys;
    It's been a long time, it seems the thread died a few years ago. Anyways, I am back in the CNCzone and would like to hear from your HP-UHU experiences in the last 10 years.

    Best regards,

    kreutz



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    Default Re: High Power UHU Thread (HP.UHU)

    Quote Originally Posted by kreutz View Post
    Hi Guys;
    It's been a long time, it seems the thread died a few years ago. Anyways, I am back in the CNCzone and would like to hear from your HP-UHU experiences in the last 10 years.

    Best regards,

    kreutz
    Welcome back.
    My two HP_UHU drives have been temporarily retired. Turns out one of the two DC Servo motors I bought from https://www.automationtechnologiesinc.com/ was not the same as the other even though they were supposed to be identical. I was milling something with LinuxCNC and when I returned back to the 0,0 position my Shumatech DRO told me I wasn't there. And the next pass was offset. So it wasn't the DRO.

    After a lot of work and research including the swapping to X motor with Y motor and a few parameters it looked like the motor was faulty. I then measured winding resistance and sure enough they were different. Explained why one motor always seemed to run hotter than the other. Discussions with Henrik Olsson who's processor module I was using didn't solve anything either.

    The motor was too old to be able to get a replacement (years past any sort of warranty point) so rather than take the chance with Automation Technologies I ordered AC Brushless Servos directly from China. Cost of one axis motor+drive was the same as just a replacement DC Brushed motor and it ran off AC and not the DC power supply.

    Now I have Bergerda motor/servo drives on all three axis and even the spindle which is also run with step/dir signals from LinuxCNC. All running from 220VAC. Fast, quiet and smaller.

    Not sure what to do with the HP_UHUs. I have two fully operational ones with Henrik's module. And two that have not been completely assembled and I believe the two original processors. I was thinking of changing my Unimat DB-200 lathe spindle over to the one motor. The one with the issues. And possibly the Z axis of my South Bend Heavy 10L lathe from the small stepper over to the bigger DC servo and then using the existing Z axis stepper for the cross slide which is currently not powered.

    Also still want to build a variable speed sand muller for green sand. With a proper reduction drive I think I've got more than enough power to spin a small muller.

    Anyway, that's where I am.
    John



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    Default Re: High Power UHU Thread (HP.UHU)

    Hello John;

    Sad story with a happy ending, I guess that it makes a lot of sense to go with the times and upgrade to AC servos, both, economically and for peace of mind.
    I never had the time to upgrade my micro mill with servo drives and to convert my 8x14" lathe to cnc. Maybe in the near future I will.

    Best regards

    kreutz



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    Default Re: High Power UHU Thread (HP.UHU)

    Quote Originally Posted by kreutz View Post
    Hello John;

    Sad story with a happy ending, I guess that it makes a lot of sense to go with the times and upgrade to AC servos, both, economically and for peace of mind.
    I never had the time to upgrade my micro mill with servo drives and to convert my 8x14" lathe to cnc. Maybe in the near future I will.

    Best regards

    kreutz
    Not totally a sad story. Learned a lot. In fact was just going through the box with the extra UHUs the day before your posting trying to decide what to do with them.

    I think the biggest problem is that nowadays the far east price of things has dropped so dramatically that projects like UHU or HP UHU aren't that cost effective. My ELS, in many ways is still way better than the current crop of Arduino based electronic gearing pretending to be electronic lead screws. But Arduino's and serial based LCD display low cost and people perfectly happy with a rotary knob and one or two buttons for parameter inputs means that custom 35 button keypads with a row of soft keys below the LCD are no longer selling. I still need to get $130 to break even on parts. The arduino model probably costs under $40.

    Add that mine used a single pulse per rev sensor, perhaps surplus from a printer because at the time quadrature encoders were well over $100 or more. Now you can get a quadrature encoder, toothed belt and two pulleys for under $20.

    I think it's the same with the HP_UHU. Here's the servo motor I was using at $149.
    https://www.automationtechnologiesin...ft-servo-motor
    The US Digital Encoders were crap and sensitive to noise so I ended up replacing them with ones similar to these at half the price of the US Digital ones that are $38.95.
    https://www.automationtechnologiesin...-v-kit-encoder
    I do have two GECKO drives like these in the box but they are only good to 80V and I wanted the full 90VDC and in fact to get over the voltage drops ran the HP_UHU's at 105VDC.
    Here's the Servo Driver that is suggested for this motor at $172.99.
    https://www.automationtechnologiesin...ver-dg4s-16035

    So let's add it up. $149+$39+$173=$361US w/o shipping.
    Slightly smaller size AC Servo from Bergerda was cheaper and has worked perfectly.
    https://en.bergerda.com/product/607.html

    Now put together an HP_UHU kit and add that you also need a decent power supply for the motors at the rated 90VDC if you want full RPM. Now if the far east stuff was priced at North American parts and labour rates then that DC Servo driver would run more like $350 instead of $173. At that point a UHU kit is a bargain. And fun to build.

    Remember it was the motor that was the problem. The Y axis worked perfectly as did X when I swapped motors. No lost position. I never did try doubling the power setting on the motor to see if that would have made a difference. Probably should have. The HP_UHU would have had no trouble handling that.

    End of ramble...



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    Default Re: High Power UHU Thread (HP.UHU)

    You are right, at that time the HP-UHU and UHU drives were a cheaper option, considering that a lot of used dc servo motors, some with encoder already, were available for cheap. The influx of new products manufactured in Asia (in the last 10 years) at cheap prices invalidated the DIY option, which is not financially better, but remains ok for only a very few that use it as learning experience, albeit a higher cost alternative in both time and $$.

    Time changes preferences, and that is true for people born around the end of the 1900s, GUIs are what they are used to. Old people, like myself, are ok with pressing buttons and 7 segment displays. But the majority of potential users are younger and need their touchscreen displays and rotary knobs.

    Modernizing the ELS will require getting rid of the old design and developing a new one, the only difference is that you already know what you want and how to do it properly. Getting a market for it will probably get difficult, so will be breaking even. So it will be only a personal satisfaction project until enough demand shows to make it profitable and, at that time, an asian contraption will appear at half the price.

    Keep on the good work!
    Regards,

    kreutz



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    Default Re: High Power UHU Thread (HP.UHU)

    Quote Originally Posted by kreutz View Post
    You are right, at that time the HP-UHU and UHU drives were a cheaper option, considering that a lot of used dc servo motors, some with encoder already, were available for cheap. The influx of new products manufactured in Asia (in the last 10 years) at cheap prices invalidated the DIY option, which is not financially better, but remains ok for only a very few that use it as learning experience, albeit a higher cost alternative in both time and $$.

    Time changes preferences, and that is true for people born around the end of the 1900s, GUIs are what they are used to. Old people, like myself, are ok with pressing buttons and 7 segment displays. But the majority of potential users are younger and need their touchscreen displays and rotary knobs.

    Modernizing the ELS will require getting rid of the old design and developing a new one, the only difference is that you already know what you want and how to do it properly. Getting a market for it will probably get difficult, so will be breaking even. So it will be only a personal satisfaction project until enough demand shows to make it profitable and, at that time, an asian contraption will appear at half the price.

    Keep on the good work!
    Regards,

    kreutz
    High Power UHU Thread (HP.UHU)-adaptorboard-7-jpg
    I have already done the initial upgrade to a PIC32 from the 8 bit PIC18. In the past I've used a 4 line display for a different project. The PIC will handle, with internal hardware, a quadrature encoder so the ability to now create the electronic gearing is there. And since the add on would plug into the existing PIC18 socket and the DB-25 jumper header everyone with an existing ELS could upgrade.

    But although the code ported without issues and runs the interrupt routine in under 3uS instead of almost 40 uS taking up far less of the 50 uS tick period the possibilities are quite interesting. Like G-Code parsing etc.

    But then I got distracted by a dual core TI part that also had hardware quadrature decoding. However other stuff kept showing up and you are right. Can't compete with Asian labour and parts costs. At the moment it's also world wide component shortages which is causing nothing but grief for me.

    Maybe in a few years the world will settle back into upgrading old iron and the HP_UHU with HO's dsPIC upgrade will be useful again.
    John

    John.



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High Power UHU Thread (HP.UHU)

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