Mark VII Motor Breakdown

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The Mark VII motor is a 1 1/8 hp similar to the Mark 5/V, but it has a double shaft. The extra shaft drives a vacuum impeller etc.

First the cap and spring and floating sheave were removed. I am fortunate to be able to do that by hand(with good retaining ring pliers). The parts are the same as the current Mark V.

Next the start capacitor is removed. The mounting bracket snaps onto depressions in the end of the capacitor etc. The leads are soldered, so I cut the wire going to the motor(there is more than adequate wire length). I will resolder it when putting motor back together.

[ATTACH]19803[/ATTACH]

An interesting 'alteration' by a PO. Not sure this was a wise move, but I will use it 'as is'.

[ATTACH]19804[/ATTACH]

The fan sheave set screw was misplaced. It should have been tightened against the key.

[ATTACH]19805[/ATTACH]

A 'problem' that is common to later versions as well. The spacer has worn INTO the fan sheave which allowed the sheave to rub against the motor end cap. This may have been the result of the set screw misplacement. The spacer sets against the bearing inner race and should rotate with the shaft and sheave and bearing.

[ATTACH]19806[/ATTACH]

Next comes removal of the end caps. This shows the 4 screws that pull the two end caps onto the motor shell.

[ATTACH]19807[/ATTACH]

This thread is linked to from https://forum.shopsmith.com/viewtopic.php?t=11373

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Before removing the end caps, make a mark on the shell and end caps(both ends) so the end caps and shell can be realigned the same later. A simple scratch across the joint will suffice. Just make sure it is 'permanent'.

The screws that hold the end caps on are quite small(but long), but typical and adequate.

[attach]19808[/attach]

Shaft end cap removed. A bit:D of saw dust buildup! Notice the bearing retaining flange that is secured by two screws through the end cap which must be removed to get the end cap off.

[attach]19809[/attach]

The vacuum end cap pulls off easily. More sawdust.

[attach]19810[/attach]

Armature removed. Notice the start switch actuator. The brass weights merely pivot slightly(when shaft rotating), but that causes the ring to move in away from the end of the shaft.

[attach]19811[/attach]

Notice the parts on the 'output' shaft end. There is both an inner and an outer retaining ring. The spacer was between the inner retaining ring and the bearing. Both rings and the spacer need to be moved away so a bearing puller can access the inner race.

[attach]19812[/attach]

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The bearing on the vacuum shaft end also has an inner retaining ring and spacer that need to be moved out of the way for the bearing puller. The end cap retains the bearing from the outer end.

[ATTACH]19813[/ATTACH]

The start switch has two contacts in parallel. This helps prevent a dust particle from holding the switch open. The contacts are closed(made) when the actuating ring presses against the two buttons on the contact leaves.

[ATTACH]19814[/ATTACH]

The end cap bearing cavity holds a flat washer and the bearing end play spring.

[ATTACH]19815[/ATTACH]

The switch is secured to the end cap by two screws and a nut on the outside of the end cap. Three washers space the switch board away from the end cap on each screw.

[ATTACH]19816[/ATTACH]

This shows the start switch contacts. The actuator presses the leaves down(in the pix) and close the contacts.

[ATTACH]19817[/ATTACH]

[holsgo]

Great motor breakdown. If you we're to break down the motors of all the types it would be a great resource. I'm serious, you need to video this stuff. You've fixed many a motor over the years on this forum.