Motor tunning

[DennisF]

Hi Guy's
I have a question for the Mach Guru's if i set the velocity over 900 in the X axis the drive fault's why would it do that and if i set it to 500 the drive never fault's but it is dam slow also i f the X & Y do not have the same setting's what would happen.
Thanks

Dennis

[Hood]

First question will depend on your hardware but I am presuming its servos when you say they fault. If it is then likely your tuning is out and the following error is being exceeded due tothe increased Velocity. Could also be the Velocity is too much for your motors, what does that correspond to in motor RPM and is it within the constant rated RPM of your motor?

For the second question, no doesnt matter as far as Mach is concerned but often best to have each axis as close as you can to one another.
Hood

[DennisF]

Hood
Yes they are servo motor's they are the bodine Big MHO they are 130 v and 2500 RPM 500 in oz's

Dennis

[Hood]

So what does the 500 in Velocity equate to, ie what is the pitch of your screws and do you have any gearing between motor and screw? Also what drives do you have?
Hood

[DennisF]

Hood
I have the gecko servo drives I think they are the 301 or 320 the motors are connected via a belt drive and pulley set up  i had everything written down as far as pitch and so forth but i can't find it now.

Dennis 

[DennisF]

Hood
 i was wrong on the motor they are baldor and they are 120 volt's i am running the transformer at 50 volts for the geckos as they can't handle more then 70 volts originally the transformer out put was 100 volts.
the thread pitch is 5 threads per inch and the ratio is 2 revs motor to one rev screw.

Dennis

[Hood]

Dennis, 120v motors running at 50v will only get 50/120 = 0.4 of the rated speed of these motors, so say yours were indeed rated at 2500rpm then because you are running 50v you could only expect to get 1000rpm and it may actually be less.
With your setup you would need 10 revs of the motor to move 1 inch so for 500IPM you would be 5000rpm which is impossible. It would seem to me that you do not have the steps per unit set correctly as 500IPM is not slow and you were saying it was.
 As said however the max you can expect to get is 1000rpm of the motor which would equate to 100IPM, not fast but not deadly slow like you are describing either.

Do you know what count encoders you have?
Hood

[DennisF]

Hood
I have just run a program and to my surprise the machine was not that slow looked to run just fine my only problem was the drive fault now that i have lowered the Velocity to 900 it seams the problem has gone away at least for the time i have run the machine.
The Encoder's are new they are HP 500 line encoder's on all drives

Dennis

[Hood]

Either I am doing the calcs wrong or something is not stacking up. With the screws and reduction you have said 900Inch per min Velocity would work out as 9000rpm at the motor.
You are talking velocity of 900 inch per min and not 900mm/min I presume?
Hood

[DennisF]

Hood
Sorry i am in  MM .

Dennis