The purpose of this document is to describe how to maintain the “Gold” series motors, PMI type U12M4, and U12M4H (UIC part number 11467000, 13570000, 40051001, and 40051002, sold before November 1995) This procedure should be performed every six months, or more frequently if found to be necessary.
Screw driver (5 to 6 mm wide)
Screw driver, small blade (2,5 to 3 mm wide)
Push in the machine’s Emergency Stop button
Turn off the machine’s power
1. Note which wires are attached to which motor terminal. Using an adjustable wrench, remove the wires from the motor’s terminals.
2. Remove the motor from the machine
3. Remove the brushes from the motor
4. The minimum usable length of the carbon part of the brushes is .240 inches ( 6,1 mm) long. If the brushes wear shorter than .240 inches, the motor’s commutator wires can be damaged by electrical arcing.
So that the brushes will not wear to less than .240 inches, we recommend that they be replaced when they become .300 inches long ( 7,62mm). Universal’s part number for a set of four (4) brushes for these motors is B26100021.
5. Check that the motor’s shaft turns smoothly. If not, then the bearings are damaged, and the motor should be discarded.
6. Using clean, dry, compressed air, blow the carbon dust out of the motor.
7. Look through the brush holes and examine the condition of the commutator wires, while turning the motor shaft. If there are any burned or damaged wires, the motor must be discarded.
8. To install the brushes into the motor, place the carbon block in the brush hole.
9. Using a small screwdriver, gently push the spring down into the brush hole. It will be necessary to reposition the blade of the screw driver several times into the coils of the spring, to make the spring go into the hole.
10. It may be necessary to push the metal tab on the side of the brush contact to make it go into the brush hole.
11. After the metal tabs have gone into the hole, use the screw driver to hold the brush contact down in the brush hole.
12. Pull the small screw driver blade out while moving the screw into place. Be sure that the brush contact’s tabs do not come completely out of the brush hole when doing this. Start the screw in the threaded hole by turning it clockwise with your fingers. If it will not turn easily, remove it, and repeat step 11. Then tighten the screw gently using the large screw driver.
13. Install all (4) brushes into the motor. Mount the motor on the machine again. Reattach the wires on to the proper motor terminals.
Machine Axis Control IM-Diagnostics Mode Overview *
*This is a generic overview for training purposes. Actual axes on the machine may differ slightly from this overview.
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