[UWP_Wes]

Hello everyone.

I am in the process of converting an Dyna Myte 2800 to a PC based control. However, I have run into a stumbling block with controlling the spindle speed.

Some background on this machine. The spindle motor is a .75kW brush-less DC motor. The motor is powered by a servo amplifier made by Servo Dynamics. This amplifier is in turn controlled by a digital to analog converter board. Spindle speed is set using a potentiometer on the control panel and an encoder on the spindle displays the speed in an LCD. The stock motor is not reversible.

While probing inside the control cabinet with a multi-meter, I crossed the probes and burned up a capacitor and a small integrated circuit in the D/A conversion board. I now have no spindle control.

I am using the CNC4PC C11G breakout board. This board has a 0-10V variable output to control a VFD. I was hoping to substitute the existing spindle speed potentiometer with the output from the breakout board. I still think this is the correct method.

The potentiometer is connected to the D/A converter board which is now not working. I cannot operate the spindle currently. I am trying to understand how the D/A works and if it is necessary to get the spindle working. I should be able to replicate the input needed to get the spindle amplifier working. I do not have a wiring diagram for the spindle amp.

I have attached the wiring diagram from the machine manual. I also have included the current connections to the servo amp (bottom of the page). I am hoping that I can eliminate the D/A board and connect up directly to the amp because I doubt a replacement D/A board is available. I am not sure how to do this without causing further damage.

I can't figure out if the "speed pulse" wire or the "VO" wire are the speed control signal. The D/A board also has an input from an encoder on the spindle, but I have no idea how it uses it

I appreciate any help anyone could give me with this issue.

[jalessi]

UWP_Wes,

What is the model number of the Servo Dynamics amp?

Jeff...

[UWP_Wes]

Sorry, the amp (and motor) is an Electro-craft.

Model - 170V
Serial # - H000993
Type - BRU-50
Part # - 9090-0541

[jalessi]

Are the connections marked on the servo amp?

Can you post a picture?

[UWP_Wes]

First pic is the control cabinet as a whole. Second is the amp. You can see there is no cover (maybe for better cooling?). The connections at the bottom correspond the the last diagram in my first post.

[jalessi]

I cant tell which connections on the amp are the -10 +10