Today I received the revised Sangmutan VFD for my NM145. The good news is there is plenty of torque at Low RPM now. The bad news... the installation instructions leave much to be desired and the spindle won't spin CCW and you may have to move the mounting studs for the VFD.
First, if you get the VFD board and follow the included instructions it may not work. Part of the instructions say to remove the orange forward / reverse wire from the NC output of PIN 16 on the break out board and put it in the ground terminal of the power input section. (This makes the spindle ONLY spin forward -- no possible way to reverse) Next a pair of wires are connected to the K1 & K2 pins on the VFD after removing the jumper already there. These are the connected to PIN 16 and Pin 16 NO on the breakout board. This becomes a spindle enable output instead of spindle direction.
However the instructions say nothing about removing a pair of jumper wires already on PIN 16 to ground. If left in place the K1/K2 signal will be shorted to ground. (This might kill the VFD -- I didn't want to test it on mine.) These wires connect PIN 1 and PIN 16 of the break out board to ground. I just moved one wire to PIN 1 and left out the jumper to PIN 16.
The AC power to the VFD attaches to a different place then before. It does NOT attach on the terminal block with the UVW wires! The incoming power ground however does get attached by the UVW terminal block... I had to slit the insulation a bit on the cable to make the wire stretch far enough.
Problems: If your version of Mach3 is configured as mine was you will be able to command the spindle to spin forward but when told to reverse it will instead stop. It gets better, when commanded to stop the spindle will run forward. It will also run forward when you hit E-stop. Pressing the RESET button on Mach3 will sometimes also cause the spindle to run. The logic of the PIN 16 relay was set up to run the spindle direction originally now we want it to be a spindle enable that is safe when mach3 quits AND E-stop is pressed.
Editing the Mach3 configuration for Ports / Pins, Outputs so that PIN 16 is NOT active low fixes the problem.
I have tried a couple of alternatives to get spindle reverse back but without any technical information about the new Sangmutan VFD I have not found a perfect solution as of yet.
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We’d like to thank you for the installation feedback of the new NM-145 VFD kit. We are happy to report that our initial customers who have already installed the first VFD kits did not report of any problems during their installation process.
Looking back at the installation instructions, I realize that some further clarity should have been given. In order to enhance the instructions, we have taken this opportunity to improve them and provide a little more history regarding the VFD kit. This change is not very difficult to install and it provides a simple way to replace the VFD in the event of future failures of the original VFD model.
As many are aware, SangMutan has taken a considerable amount of time in developing a new VFD model which improved the low end speed torque. Our initial testing of the new VFD, showed the torque to be exceptionally good. We also found the operational control changed in comparison to the original VFD. Specifically, when the PWM speed control signal is removed, the spindle will most often have some residual slow rotation. This has been overcome only by using the VFD disable input. We have had numerous discussions with SangMutan about these findings and decided that we were not prepared to delay deliveries any longer to accommodate additional changes. We opted instead to use the VFD disable input feature to ensure shut down of the spindle when the PWM speed control is removed. To interface the VFD disable to the C11G breakout board, we used the relay control (pin 16) to disable the VFD. This also means that the direction control originally used from pin 16 could no longer be used for this purpose. Since we know of no one that requires CCW rotation under program control, we hard wired the direction control to CW. Rotational control under program can still be used; however, control signals for the 4th axis are the only signals available. For those who might desire program control for rotational direction and do not require a 4th axis, we can provide a wiring change upon request.
As far as mounting the new VFD, we were told that the mounting holes for the unit were to be the same. To our surprise, this was not so. However, on the chassis plate, we have already 2 sets of pre-machined holes. It works out very close to use a combination of the two sets to mount the VFD. So two out of the four stand offs will have to be relocated to accommodate this.
The performance of the NM-145 has shown to be very tight and accurate. We have observed that with the improved VFD, the low spindle power has also increased and has upgraded the mill’s capability. We will continue to listen and work in order to improve our machines along with your suggestions. Rest assured that we listen to all of what you have to say. This dialogue has helped us to date to make many improvements to the current machine productions.
We thank you again for your constructive and technical input.