Recently Purchased Series II, can i run it with a VFD??

[levig14]

I would have thought there was sufficient for it to still run, It looks a little to worn to turn it down, if you do you may have to undercut it, which to relieve a little of the insulation between segments using a fine hack saw blade with the set of the teeth ground flat.
Later com's have a wearable substance instead of the old Mica that was once used that removes the need for undercutting.
Al..

I was wondering about that, i actually watched a video last night of a fella turning the commutator down, and then opening up the insulation space with a small grinder.

[Al_The_Man]

A grinder is not a optimum tool, traditionally the saw blade is snapped to a 3" to 4" length and clamped to a straight shaft and handle for ease of use.
Some are oscillated by a jig saw like motor unit.
Al.

[levig14]

any suggestions for the best thing to use to clean out this dirty old pig? Whatever i use i expect i will need to use a lot of it. I wonder if over the years some of the oil from the gearbox hasnt seeped into the inside of the motor, it is pretty darn grimy.

[Al_The_Man]

Most de-greasing alcohol based solvents, I have used kerosene in a pinch, make sure it is drained and dry before re-assembly,
Clean the brush gear well and remove any grease, test the brush tension springs. And clean the brushes off well.
Al.

[levig14]

Well, i got all the gunk cleaned out of it, hope to get it on a lathe today and get the commutator turned back flat, and see if she will spin on her own power. After cleaning the bearings spin very free, but now feel dry, is there any oil i can add that will stick with them, or do i need to just go ahead and replace them? Pics below, well because a story sucks without pictures.

[CNCMAN172]

I would definitely replace the bearings, you have taken the time to tear it all apart and are truing up the commutator, go all the way replace the bearings and even the brushes if you can find them and you should be good to go provided there are no shorts in the windings.

Russ

[levig14]

SUCCESS!!!!!! Got the motor re-assembled last night, and just used a 12 volt car battery to test. She spun up like a brand new motor! Quiet and smooth, granted it was running pretty slow, but running none the less. Now i will have to go through and make sure all of the other wiring on my machine is correct, i dont really want to burn up another motor drive! Thanks for all of the help everyone! I think i finally located a legible copy of a wiring schematic, it appears to be a little newer than my machine, but matches up pretty well. I went ahead and attached the document, just in case anyone else would happen to come across this thread with the same troubles as I.

[Al_The_Man]

Here is a manual for the BP11.
That also may help.
Al.

[levig14]

Here is a manual for the BP11.
That also may help.
Al.

Thanks for the manual! I actually just received my hard copy from Ozark manuals yesterday, it is flawless! All of the wiring looks to be in good shape in my machine, and doesnt appear to be messed with, so hopefully it will be as simple as hooking the motor leads back up and turning it on.

Gonna show my ignorance again, as i am not even the least bit familiar with SCR's, do you think the motor not running before would have blown out the scr like i experienced? The insulation grooves in the commutator were packed solid wit grease. Just not sure what effect this would have up stream.

[Al_The_Man]

Generally it would just stop the motor from operating, but one possible cause is carbon build up and tracking to GND etc.
Al.

[levig14]

Didnt get a whole lot of time over the weekend to work on my mill, however before i left for the weekend, i hooked the motor back up to the machine and gave it a whirl. It runs in both directions with the switch as it should, however it only runs very slowly. I checked with a meter, and there is only 5.5-6v going to the motor. Is this motor supposed to operate like the other power feed, with adjustable speed etc?

[Al_The_Man]

The drive you repaired was for the table feeds, no?
Is there a separate drive for each motor?
If so is how is the rpm controlled for the Knee?
Maybe it is a pre-set pot.
Al.

[levig14]

I am pretty sure there is only 1 speed control. Below is a picture of my cabinet, the only thing not seen is the terminal strip. According to the wiring diagram i posted a few posts back, it appears that both drive motors run through the same speed controller, unless i am reading it wrong.

[Al_The_Man]

If the controller is working on other motors, then I would assume when selecting the knee, a preset pot would be switched in at that point.
I will see if anything shows on the print.
You also must have selection relays for the relevant motor?
Al

[Al_The_Man]

OK I see that the same drive feeds the motors and the knee is selected by 2CR,3CR and interlocked through the selector switch.
There does not appear to be any pre-set pot switched in when knee is selected, so there must be other things at work.
Does it make a difference if rapid switch is used?
Al.

[levig14]

OK I see that the same drive feeds the motors and the knee is selected by 2CR,3CR and interlocked through the selector switch.
There does not appear to be any pre-set pot switched in when knee is selected, so there must be other things at work.
Does it make a difference if rapid switch is used?
Al.

No, the rapid has no effect on its operation.

[levig14]

Just grasping for straws at this point. But could the dynamic braking delay have anything to do with it?

[Al_The_Man]

Can you try another load to test in place of the knee motor?, even a lamp bulb to see if you get full voltage.
I couldn't see anything on the print that that might affect the knee only?
Al.

[levig14]

Can you try another load to test in place of the knee motor?, even a lamp bulb to see if you get full voltage.
I couldn't see anything on the print that that might affect the knee only?
Al.

I will give it a try tonight and see what i get!

[levig14]

Can you try another load to test in place of the knee motor?, even a lamp bulb to see if you get full voltage.
I couldn't see anything on the print that that might affect the knee only?
Al.

Your suspicions are confirmed. I wired in a 100w lamp last night, and was able to vary the voltage as normal. I assume this means i am not quite out of the woods with my knee motor yet.....