Vertical Drilling Motor, Type GE752, GEK±91584D
3.Continue tapping as described in Step 1 until the 0.753 dimension falls between 0.751 and 0.755.
4.If, due to excessive pounding, the inside dimen- sion becomes less than 0.751 in., file back to size with a fine mill file.
Additional repairs can be made to restore damaged brushholder bodies. Brushholder damage is fairly typi- cal when flashovers have occured, resulting in some burning or melting of metal at the corners of the brush- holder. Metal thus removed can be restored according to the following instruction, unless more than 1/4 in. buildup of metal is required in the affected area, in which case the brushholder should be scrapped. Proceed as follows:
1.Thoroughly clean the affected area by wire brushing, and grind off any metal flow resulting from a flashover.
2.Apply a suitable brazing flux such as GE±A10B15 to the area to be built up.
3.Insert a carbon brush into the brushholder to pre- vent the brazing material from flowing into the carbonway.
4.Using a brazing torch and a 1/16 in. diameter brass brazing rod, puddle in sufficient metal to restore the metal that had been removed.
5.Check the carbonway for size with the ªGo/No± Goº gage after the brushholder has cooled to room temperature.
6.Resize as required using the preceding method.
Brushholder Sleeves
spots caused by flashovers. Replace any damaged brushholder or one having a damaged sleeve.
WARNING: MEK is a volatile solvent. The fumes should not be inhaled. Use only in a well±venti- lated area and take adequate precautions to pro- tect eyes, skin and hands.
NOTE: Never paint these sleeves. Periodically wipe them clean with a dry cloth or a cloth dipped in an approved non±oily cleaning sol- vent.
Inspect the brushholder cables and make sure all terminal bolts and all brushholder clamp bolts are tight.
Brush Spring Pressure
Lift the brush pressure fingers to the ªtoggled±upº position, Fig. 5, and check for free movement of the spring assembly.
Inspect the brush springs for obvious failure or dam- age. Check brush±spring pressure by comparing spring pressure with a spring known to be good. Refer to the DATA section for brush spring±pressure value.
BRUSH PRESSURE FINGER (IN TOGGLED±UP POSITION)
TEFLON | PRESSURE | |
SLEEVES | ||
SPRING | ||
| ||
| CARBONWAY |
BRUSH±SHUNT
TERMINAL
SCREWS
Use a clean, lintless cloth and wipe dirt and grease from the Teflon* brushholder sleeves, Fig. 5. If neces- sary, use a cleaner such as MEK (methyl ethyl ketone) to clean the sleeves. Inspect sleeves for cracks and thin
FIG. 5. BRUSH SPRING ARRANGEMENT.
E±18963.
*Product of E.I. duPont de Nemours Company.
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