G0704 Fluctuating spindle speed

[prcdslnc13]

Hey Guys! I got my new G0704 2 days ago and am really loving it except for one thing. The speed controller on the spindle motor does not seem to be stable. I ran the break in for the spindle bearings just like the manual stated but the speed jumps all over the place while the spindle is turning. Ive seen spikes as much as 500 RPMs when I start spinning at 1000. For example Last night, I started at 1000, it jumped to 1100, 1300, 1490 then back to 1100 then down to 980.

Its not just the tach thats wrong either the spindle is changing speed too. I havent had time to call grizzly yet. Do you guys have any ideas?

thanks,
Joe

[Connor9220]

Bad pot or flaky motor controller.

[prcdslnc13]

Awesome, so probably another bad board. I love buying broken stuff

[LUCKY13]

Doesnt that board have some tunning pots? Look into Hoss thread and see what he did with his. I know he replaced later on but I believe he did some tuning on it also. It sounds to me like either there is a VR ( tunable resistor on the board) that is setting on the edge of a ajustment, or the motor itself has parts of the rotor that are loosing connection, either through the wiring, or brushes not seating good. So check brushes and springs if it has them.



Jess

[prcdslnc13]

Do you know if thats in the first or second thread? 500 pages of thread is alot to sift through

[LUCKY13]

NO I would have to look through it myself. I do remember there being a max speed VR for sure.


Just for a quick way to go about and check these just take it apart,cover off, or out of the machine. What ever it takes to get to it. Look for any VR's on the board. Make you a diagram on paper of the board with all VR's marked with there possition on the board, and there possition with ajustments.

Then make a mark on the VR's themself so you can get back to there settings. Now take each one and give them a turn back & forth and return back to possition they where in ( unpluged no power).


If any are not making good contact this will help them get seated/connected and you will still be at factory settings. If one has a bad spot which will not connect good you might try to go beyound or before its bad spot. Ofcourse this would take LIVE testing of each one to see if such problem is going on, so much gare would needed to be sure you dont short something out ( like touching the back of the board to ground or such, or touching the board and getting shocked/burnt yourself)....... Be care if it comes to this, but its not as bad as it sounds. It just easy to make bad mistake if not paying attention.


ANyway all it would take is a piece of dirt, corrossion in a VR to make it act this way so doing the turning of each would help to clear this out.


Jess

[RTTIM]

Do you know if thats in the first or second thread? 500 pages of thread is alot to sift through

Try this link to one of his video's....

http://www.youtube.com/watch?v=SfrEuHpZwv8]G0704 Motor Controller RPM and Torque Increase - YouTube

[Doug Laser]

Contact with your supplier and change a new spindle motor asap.

[prcdslnc13]

Grizzly is supposed to be getting back to me on monday, Well see what they have to say. The issue doesnt seem to be getting any better, but its not getting worse at least.

[Starleper1]

Check you IR pot. Make sure it's not turned all the way up or something alike. It basically regulates motor speed to try and keep a constant RPM when under load. I know the motor isn't under load, and still is fluctuating, but it might be worth looking at.


KBIC Manual Page 19 will explain how to recalibrate it, if necessary.

It should look something like this...