Centroid Community CNC Support Forum

If you don't, remove the tripper from one side of the axis. (The one you won't home with)
Setup up the soft limits properly.

Marty

Hello!
Today I asked a friend for help and we were taking measurements of the voltage and current values.
Since I don't have these values ​​written on my motors, I think it's important to measure them before taking apart the old control.
To take the measurements i used JOG in maximum speed.
The measured values were:

X axis ( In the output of transformer: peak 3,8 amps , average value 2,8 amps In the rectifier output 0,7 amps )
Y axis ( In the output of transformer: peak 2,7 amps , average value 2,2 amps In the rectifier output ... amps )
Z axis ( In the output of transformer: peak 2,25 amps , average value 2,1 amps In the rectifier output ... amps )

Transformer output voltage to driver : 26 V
Transformer output voltage to servomotor : 52 V

Limit switches voltage: 3 V

Which values ​​should I pay more attention to? Should I use the existing rectifier capacitor or should I use the one supplied by Centroid?
Should i take more measurements before a take apart the old control?
Regards

Limit switch voltage no big deal. You are only using the contacts and you should use the 24VDC SIP resistor pack usually pre-installed on AIO DC. The inputs stand at 24VDC and need to be taken to COM to activate them.

There should be a LARGE capacitor and a bridge rectifier that rectifies the AC coming from the transformer to DC. Find it and measure across its - and + terminals.

I assume you have no current schematics for the machine?

How did you get those current (amp) measurements? Just putting an AMP probe on the transformer secondary wires and jogging the machine around? That won't give you true DC current for the motors. You need to factor in cutting forces.

Maybe Marc/Tom will chime in with a suggestion on what they do when there is no legible label on the motors. Remember you still have to tune the servos. You need a starting point for the PID settings. You can see how the settings do that are set in CNC12 as shipped. But I believe you are going to have to get the current settings close.

Marty

The capacitor is inside one black box where I think the servo drivers are around ... I will have to open the box ...
Yes, I measured the current at the output of the transformer while JOG at maximum speed. I can always put a piece to work and measure the current in effort. In my case I think that this is the key point to have a good final result, which is to discover the motor currents. All help is welcome! Thank you

Transformer output voltage to driver : 26 V
Transformer output voltage to servomotor : 52 V

Were those measurements AC Volts, or DC Volts?

What is the DC voltage that you measure across the terminals of the large capacitor (which should be the DC Voltage going to the drives)?

The output of a transformer is an AC voltage.
Typically, the input to a DC servo drive is a DC voltage.
In between the two is a rectifier (diode bridge and capacitor) which converts AC into DC.
It is important to specify what you are measuring.

Post pictures of what and where you are measuring....
You can do that by clicking on the Full Editor & Preview button below the box you type your message into, and then clicking on the Attachment's tab, also under the message box, and pointing to where you put the pictures on your computer.
Marty

cncsnw wrote: ↑Fri Feb 12, 2021 1:51 pm

Transformer output voltage to driver : 26 V
Transformer output voltage to servomotor : 52 V

Were those measurements AC Volts, or DC Volts?

What is the DC voltage that you measure across the terminals of the large capacitor (which should be the DC Voltage going to the drives)?

The output of a transformer is an AC voltage.
Typically, the input to a DC servo drive is a DC voltage.
In between the two is a rectifier (diode bridge and capacitor) which converts AC into DC.
It is important to specify what you are measuring.

The voltages and currents were measured between the transformer and the module containing the drivers, so they are AC. To measure the voltage at the output of the rectifier, I suppose I will have to open a cube-shaped box with the drivers around and the condenser in the middle. The only measured DC amperage was on the X axis, at the output of the driver module for the motor where the cables were accessible and where in the JOG mode 0.7 amps was measured

The information i have:

Motor Voltage: 70 Volts
Motor Torque (X and Y axis) : 280 ozf.in (17,5 lbf.in or 2 Nm)

Motor Brand: i think is Magnetek (4040D-35 ...assembled in Mexico by Indiana Genera)l

martyscncgarage wrote: ↑Fri Feb 12, 2021 1:57 pm Post pictures of what and where you are measuring....
You can do that by clicking on the Full Editor & Preview button below the box you type your message into, and then clicking on the Attachment's tab, also under the message box, and pointing to where you put the pictures on your computer.
Marty

I will do that