411 Full power without motion

[johnballard]

They vintage 1997, model MTE-4070, part FMD0750B-00

[johnballard]

Centroid repaired my AllInOne-DC - yea!

I'm starting a fresh install on my Lagunmatic 250. First step is to follow the bench test setup.

I changed out the bearings in my Y-axis DC Motor (MTE-4070 with 1000L encoder), but it still 'coggs'. My concern is that the drive will never be able to hold the shaft at the right position and will oscillate at high current. I think I counted 21 positions that the shaft will rotate to. I have browsed eBay for a replacement, but prices range from $50 to $1200. What would a good used brushed dc motor cost?

[martyscncgarage]

You do NOT have to use the exact same motor. You could use a 27lb-in SEM, Glentek, Centroid etc. You can adjust the servo amp draw on the All in One DC on a per axis basis.
What you do need to do is figure out the DC Bus voltage and find a motor that will work with that voltage. Not terribly hard to find.
What is your Bus voltage?


Marty

[aamir]

Jhon
Your motor A+ or A- may be open at any angle of motor
Can u check with the multimeter A+ and A- continuity in 360deg
If it's open on slow run it will some time give full power msg

[aamir]

Another of my observation when A+ and A- it open any any specific angle motor run but jerky motion and take more current then usual .

[johnballard]

Aamir, I’m not quite sure I understand what you are describing.

The cogging effect I see is with power off and the red and black leads are open (not connected). If I put 12v on the red and black the motor seems to run fine - just like the other two.

Are you describing a short or open circuit in one of the windings?

[cncsnw]

What Aamir is describing is an open circuit, in only a narrow part of the motor rotation.

A fairly reliable way to find and locate such a problem is to repeatedly run moves like:

Code: Select all

G1 G91 F0.5 Y0.5
G1 G91 F0.5 Y-0.5

At that slow creep speed, it is almost certain to stall at any dead spot. If it stalls, mark that shaft location; turn it slightly by hand; and try the move again. If it repeatedly stalls in the same shaft position, you have a dead spot.

What you (John) are describing sounds a little like a short or internal contamination, but I do not know enough about motor construction to say for sure (why 21 evenly-spaced hesitations?)

Are the X and Z motors the same make and model? Do they exhibit this same "cogging" behavior?

[johnballard]

X and Z are the same motors. They do not exhibit the cogging effect.

My AllInOneDC was fried. I cannot run commands. I do not want to connect this motor back onto the machine for fear that it will fry my drivers again.

[cncsnw]

Since X and Z do not have the cogging; and there was a blown component in the Y axis section of the Allin1DC, I think you are right not to risk running this motor on the control.

Bite the bullet and buy a known-good motor.

[martyscncgarage]

I have an SEM MT30M4-38 DC brush servo motor. 26lb in. 3600 RPM, 8.6A, 140v
I don't know what your bolt pattern is. And this would need an encoder.