(PROBLEM SOLVED) PM940 CNC VFD spindle question

[rodjava]

I fired up my PM940 cnc today and the VFD would not turn on. I notice that when I turn on the spindle on the Mach3 control panel, the KA1 "relay?" in the electronics cabinet turns on and off but this does not turn on the VFD. I reset all the breakers that are lined up on the left hand side of the cabinet which did not affect the VFD. Am I missing something that I should be trying?

Any help would be appreciated.
Rod in San Francisco

 

[B2]

Hi Rod,

Not for sure if I can help. Or, since your post is a month old, have you already solved your PM940CNC problem? If you have solved it I a curious as to what the problem was.

So, I have the same machine and can supply you with a scanned copy of the Users manual if you do not have it. It has some very limited circuit diagrams in it. You may also want to download the Delta VFD manual. It is hard to see if you have the same Delta VFD that my machine has in it the model Nos. are on the side of the VFD. (However, since VFDs are just programable computers controlling power semiconductor devices for switching the current to the motor, the 400 page manual can seem quite obtuse if you do not already have an understanding of how they work. However the manual is available, which is more than can be said for some parts.) If there is a VFD problem their maybe a Fault code displayed on the VFD LED readout? If I recall my VFD is a Delta Model # VFD-015-E-21 (which means 015=> power rating 1.5KW or 2 HP motor, E=> VFD Series, 21=> Input power=220 1Phase.

I believe that KA1 and KA2 are indeed small relays which are use to apply control (logic) signals to the VFD to cause the VFD to run the motor either CW or CCW. Since you indicated that the KA1 switches on and off but that the motor does not start you may wish to check to see if the signal via the relay is actually arriving at the VFD. You might simply also want to try to run the spindle in the CCW direction (KA2 relay). If by chance you have over looked it and the spindle speed is set to a low rpm the motor may not start. The VFD speed it determined by a DC voltage between 0-10volts DC applied to the VFD via the n-Motion box. If there is zero voltage arriving or it is very small, the motor will not appear to run. If 10volts is applied the motor should run at maximum.

It is not clear to me why the n-motion electronics do not apply logic signals directly to the VFD, but then I have not studied this Delta VFD operation and my info on the n-Motion controller is very limited. I have been setting up an Hitachi VFD and electronics to run a lathe and in that VFD, if one applies both a CW and a CCW active logic signal simultaneously to both VFD inputs the VFD will actually shut down the motor if running (or not start if not already running). The VFD inputs that are in play are probably the MI1 and MI2. You can trace the wires from the KA1-2 to the VFD. In my machine the wires are numbered on both ends and so the tracing is not difficult.

If need be we could do a compare between you machine and mine.

Dave

 

[rodjava]

Hi Dave,
I can't thank you enough for chiming in with your suggestions. Yes, my cnc is still inop as I could not figure out why it would not fire up. It's not like it was running and then suddenly stopped. I casually use my cnc about once a month. This time it would not fire up at all. So I was thinking it was a breaker or relay issue. I reset all the breakers but didn't do much with the relays because I didn't know what relays were what. Yes, I could use just the scans of the electronics is you have them.

I'm going to play around with some of the setting you mentioned. So, thank you very much for your help.

Rod

 

[macardoso]

Rodjava,

Do you have a multimeter (DMM)? Can you provide some pictures of the inside of the cabinet or a wiring schematic? I'd be happy to help you troubleshoot. Shouldn't be too had.

-Mike

 

[rodjava]

Rodjava,

Do you have a multimeter (DMM)? Can you provide some pictures of the inside of the cabinet or a wiring schematic? I'd be happy to help you troubleshoot. Shouldn't be too had.

-Mike

Mike,
Thank you too for help. Yes, I have a mulimeter. I will track down another members pic of the electronics enclouser which might help. My cnc is positioned only 12 inches away from a wall. I had to remove both doors in order to access the breakers and what not. So It's a real tight fit.

Rod

 

[rodjava]

Mike,
Thank you too for help. Yes, I have a mulimeter. I will track down another members pic of the electronics enclouser which might help. My cnc is positioned only 12 inches away from a wall. I had to remove both doors in order to access the breakers and what not. So It's a real tight fit.

Rod

Mike here are some pics from other members of the same cnc.

 

[macardoso]

OK, that's a solid start. Do you have a manual with a wiring diagram?

 

[rodjava]

No manual, but another member, Dave, mentioned he can send me some scans. I'm still waiting for Dave. I'm grateful for everybodys help, so I'm not being pushy.

 

[macardoso]

See if you can get a picture under the front cover of the VFD where the digital wires land. I expect the problem to be either A) VFD power input, B) Digital signal to VFD, or C) VFD fault.

 

[rodjava]

See if you can get a picture under the front cover of the VFD where the digital wires land. I expect the problem to be either A) VFD power input, B) Digital signal to VFD, or C) VFD fault.

Here are some actual pics i took. Let me know what more I can add.

Also,I would like to eliminate any Mach3 issues. I normally turn on the spindle via the Mach3 control panel by first setting the speed and increments. What is the gcode to start and stop the spindle?