Motor Question

[erik_f]

I just got done swapping the new Alpha X and Y car out from the old PRT style...I had to put the right motor on the left side and the left motor on the right side for the x car and for the y car as well (I'm using double motors on the y)...I was worried that the machine would run backwards...but it is running properly...I guess I'm confused as to why...I thought the motors were wired in reverse polarity for each side...so they would be specific to a right or left side...or are all the plugs for the motors wired the same...but the interconnecting wire between the motor and control box is where they do the actual change. I'm guessing that the has to be the case since my machine is working in proper order. I'm just curious mostly. I am running the PRT motors still...but with the addition of a second y motor now...I was hoping to be able to jog faster than what is reccomended...I tried some higher speeds last night for jogging...but it seems that there is some sort of limiter in the software? It didn't seem to get any faster after about 5 ips...has anyone gone faster than SB reccomend with the PRT motors...or is it pretty much best practice to stay within the reccomended limits. Thanks
Erik

[Brady Watson]

Erik,
The 2 X motors are wired to run in opposite directions. I believe that the black and green wires in each Wago connector are opposite in orientation. These wires effectively send direction information to the stepper. The other wires send step data. On PRTs, if the tool is running in opposite directions, you can swap the wires. You cannot do this on an Alpha. As a reminder, never fool with the motor wires with the control box on. You WILL destroy the driver(s).

Yes, there is a limit of 6 IPS on PRTs. An additional Y motor will only increase the force of the Y carriage, not the speed. Speed is a function of the voltage going to the motors. As your machine sits, you would be hard pressed to Jog at a speed greater than 5 IPS due to the voltage of the power supply. You can set the tool at a max jog speed of 6, and then tell the machine to go 60". You can use the timer in the software or a stopwatch to measure the time it takes to go this distance, then divide the distance by the time it took to go that distance to calculate the true jog speed. Keep in mind that the Jog ramp settings will alter your speed a little since nothing accelerates from 0 to max speed in an instant.

-Brady

[erik_f]

Thanks,

Well everything is working A-OK...I was just confused that the machine was running properly...I was sure it was going to run in reverse...so it must be the way the cables, not the motors are wired. I haven't had time to cut anything yet...but the double y motors and the Alpha cars have me pretty excited...CNC machines kick ass!

Erik

[gerald_d]

Erik, there is a GPS receiver in each motor that sends a signal back to Durham telling them where you installed which motor. They have an arrangement with your utility company whereby a "data packet" is generated and that sits at your power outlet waiting for the first switch on. Then this packet installs itself in your Start.ini file and everything works right. (Except for the guys who run on generators)

[erik_f]

I feel sorry for the poor sap that runs on generators...cause if he were like me...he would have no idea what was going on. Goll dang it, them there folks at the Shopbots is pretty smat, I mean smart.