GE HUB MOUNTING Hub Fitting, Hub Mounting, GEK±91584D, Vertical Drilling Motor, Type GE752

GEK±91584D, Vertical Drilling Motor, Type GE752

3.Attach the brush±shunt terminals to the brush- holder body under the screws provided.

4.Inspect the interior of the machine for foreign ob- jects. Install the commutator covers on the motor and check for proper fit and latch operation.

5.Clean the terminals.

HUB MOUNTING

Hub Fitting

NOTE: GE does not supply the hub for vertical drill motors. This procedure is included for cus- tomer use as a reference when installing the hub.

To prevent a hub from slipping, it should have at least

75 percent fit on the shaft; i.e., at least 75 percent of the tapered bore of the hub should be in contact with the ta- pered fit on the shaft. Before mounting a hub, check and correct the fit as follows:

1.Lightly cover the bore of the hub with a blueing compound such as Prussian Blue.

2.Snap the cold hub forcefully onto the shaft.

3.Mark the relative angular position of hub with re- spect to the shaft.

4.Remove the hub from the shaft. A convenient method of removal is by the use of two finely ta- pered steel wedges (hardened and ground) which are carefully driven between the hub and the bearing outer sleeve on the shaft.

5.Inspect the taper fit of the shaft; blueing of the hub bore should now show on the shaft. If at least 75 percent of shaft surface shows traces of blue- ing, the fit is satisfactory. If, however, only a few spots of blueing show on the shaft, the fit is not satisfactory.

6.Dress down the blue spots on the shaft very light- ly with a fine emery cloth such as No. 400A Trie- mite.

7.Blue the hub bore again (see Step 1) and repeat Steps 2, 4, 5 and 6. Be sure to place the hub onto the shaft in the same position as marked.

Generally, the fit will be improved, but the forego- ing procedure may have to be repeated several times to obtain a 75 percent fit.

Under no circumstances use a lapping com- pound since lapping will produce a shoulder at the large end of the tapered fit. A shoulder will prevent a perfect fit when the hub is mounted hot; i.e., when it is mounted in the advanced posi- tion.

8.After a good fit has been obtained, thoroughly clean the shaft and the hub bore to remove all blueing, oil or grease. Then mount the hub.

Hub Mounting

1.Thoroughly clean the hub fit on the shaft and bore of the hub (see the procedure in the Clean- ing section). Remove any scoring on the shaft or hub bore.

2.Spot the cold hub on the shaft by hand and check for at least 75 percent fit. See the ªHub Fittingº section. If necessary, dress the shaft to obtain this fit.

3.Trial mount the cold hub onto the shaft. Measure and record the position of the hub with respect to the end of the shaft. Take measurements with a micrometer advance gauge similar to that shown in Fig. 41. Zero the gauge.

Mark points of measurement, and mark across the end of shaft and hub face so that the hub, when heated, can be mounted in exactly the same angular position, and so the advance mea- surement can be made from the same point.

4.Mount the hub hot onto the shaft so as to secure an advance from the cold position to the hot posi- tion along the axis of the shaft as indicated in this section. The ESTIMATED difference between shaft temperature and hub temperature (temper- ature rise) which will provide this advance is also given. The temperature difference is only an esti- mate and should be adjusted (if necessary) to provide the advance within prescribed limits.

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