NEED HELP WITH 3 PHASE POWER REQUIREMENTS FOR ROBOTS

    Hi Guys,


    I finally found a used Yaskawa Motoman UP6 robot arm with XRC controller and I need help with powering it...


    I have single phase residential 220/240V power and I'm considering a Rotary Phase Converter to make 3 phase power for the robot.


    I've been on the phone with a few manufacturers of RPC's and I want to get some input on what they are telling me...


    My UP6 robot has a payload of 6KG and uses 3 phase 220V power. kVA rating is 1.5kVA, and Horsepower is supposed to be about 1.5 as well.


    I am proceeding with the knowledge that the voltage requirements are critical, and there can't be any voltage fluctuations mote than about 4%.


    Looking over the websites for RPC manufacturers, the common thought is to DOUBLE the Horsepower needed to find the right size RPC.


    So if I conservatively rate my robot at 2HP, I would need 4HP. I have priced a few RPC's from American Rotary and North American Rotary, and they both have 5HP converters that seem like they would be a good fit. But when I called these companies, they immediately tried to up-sell me on more expensive RPC's: Either 10HP models or Extreme-Duty models which are about double the price.


    Can anyone tell me what I should be looking for? Is it the size of the Idler Motor/Generator or the Circuitry /Capacitors/Relays etc. that will determine if the unit will power the robot without any faults or damage?


    Is there some way to tell the Peak current that the robot could draw - and how this affects the stability of the 3 phase converter?


    Many Thanks,


    Deke

    Well, according to this .pdf I found, a motoman UP6 has a 2KVA rating. According to random KVA to HP websites, that ends up being a bit over 2 HP. I think you would be fine with a 5HP unit.

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    Hi Nation,


    Thanks for your response and help.


    Some members on the forum have said that robots can't use the 3 phase power that comes from a rotary phase converter, and I'm not sure exactly what issues I should be looking for, or whether they are just trying to burst my bubble.


    I thought this was true for VFD's because they chop the sine wave and distort the power with weird harmonics and noise, but I thought that RPC's produced a generally clean sine wave. I thought the only potential issue was the voltage range that had to be within a certain tolerance, and that the RPC had to be large enough to handle current demands.


    Do you know anything about what I should be concerned with?


    Many thanks,


    Deke

    one of the problems with the robot is that it is not a constant load. in fact the robot is quite the opposite, changes are random and very dynamic - one moment robot is waiting and drawing very little power, the next moment it is accelerating and drawing a lot of power, and just after that it is decelerating and motors are working as generators. depending on robot controller brand and configuration this energy is burned off (using ballast resistors) or returned to the grid or in this case RPC. my understanding is that this is why RPC need to be couple of times larger so that changes in load can be easily absorbed.

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    Hi Panic Mode,


    Thanks for your reply. That really helps explain why there are so many varying opinions about this, with some people swearing that you can't use an RPC at all, while others say they used one and it worked fine.


    It seems like there are so many variables based on the particular design of a robot that I would probably need an advanced degree in Electrical Engineering to really understand what is going on from one second to the next... So I'll leave that solution aside for the time being... I'll try to get some more detailed power requirement info from the Yaskawa product techs... I don't know if they would be able to tell me anything that would help.


    If I had to choose between the RPC's sheer power-handling capacity in Amps - versus the stability of the output voltage (how much variation there is above or below 208VAC... ) which do you think is more critical?


    I wonder if any type of voltage regulator would help on the output of the RPC as well...


    I'd be interested to hear any further thoughts you have...


    Many Thanks!


    Deke

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