Happijac lubrication
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Forum Discussion
I'll add a bit more to KKELLER14K's excellent thread on HJ maintenance regarding servicing the motor.
The motor is a simple DC power drive, with a permanent magnet stator. It is important to check the motor for several points: 1) commutator wear, burning or degradation, 2) brush wear, 3) bearing lubrication.
Motor disassembly is simple, just remove the two long screws holding the commutator and end bearing. Check the commutator for wear, burning or glazing. It's a good idea to remove any glazing with a 400 grit sand paper, making sure to remove all residual grit after cleaning. I used a lathe to turn the armature. If there is any burning on the commutator or wires, you may need another motor. See photos.
Commutator showing minor glazing
Cleaning commutator on lathe
The length of the brushes is important. I'm not too sure how long they are when new, but they shouldn't be shorter than, say, a 1/4" or so. Inspect the brushes to see if they are still solid, with no broken pieces. Here's the tricky part with the brushes - holding them back in their brass holders while inserting the commutator / armature in the end bell bearing. To make this easier, I made a couple of small brass clips that hold the brushes in place while inserting the armature in the bearing. See photos.
Inserting Armature into brush housing using clips
Brush restraint clips
Now comes the tricky part. When you insert the armature in the stator (motor housing) the magnet will "suck" the armature into the housing and pull the commutator from the end bell. So, I connected a small screw type hose clamp to the end gear on the armature (see photo) to hold the armature in place while assembling the motor. It worked great.
Hose clamp on armature gear end to hold end bell in place
Note that the wires coming out of the end bell are not sealed. I placed a small amount of sealant in this hole to make sure there would be no water intrusion.
Regarding bearing lubrication - be sure to note any shims (thrust washers) that come out of the lower and upper bearings and replace them EXACTLY the way they came out. Lubricate the bearings with a light machine oil, making sure that the bearing surface on the armature is not scored and/or burred up too much. If there is scoring or burring you may need to replace the motor (or machine the armature bearings and replace the bearing inserts - not too easy).
The motor is a simple DC power drive, with a permanent magnet stator. It is important to check the motor for several points: 1) commutator wear, burning or degradation, 2) brush wear, 3) bearing lubrication.
Motor disassembly is simple, just remove the two long screws holding the commutator and end bearing. Check the commutator for wear, burning or glazing. It's a good idea to remove any glazing with a 400 grit sand paper, making sure to remove all residual grit after cleaning. I used a lathe to turn the armature. If there is any burning on the commutator or wires, you may need another motor. See photos.
Commutator showing minor glazing
Cleaning commutator on lathe
The length of the brushes is important. I'm not too sure how long they are when new, but they shouldn't be shorter than, say, a 1/4" or so. Inspect the brushes to see if they are still solid, with no broken pieces. Here's the tricky part with the brushes - holding them back in their brass holders while inserting the commutator / armature in the end bell bearing. To make this easier, I made a couple of small brass clips that hold the brushes in place while inserting the armature in the bearing. See photos.
Inserting Armature into brush housing using clips
Brush restraint clips
Now comes the tricky part. When you insert the armature in the stator (motor housing) the magnet will "suck" the armature into the housing and pull the commutator from the end bell. So, I connected a small screw type hose clamp to the end gear on the armature (see photo) to hold the armature in place while assembling the motor. It worked great.
Hose clamp on armature gear end to hold end bell in place
Note that the wires coming out of the end bell are not sealed. I placed a small amount of sealant in this hole to make sure there would be no water intrusion.
Regarding bearing lubrication - be sure to note any shims (thrust washers) that come out of the lower and upper bearings and replace them EXACTLY the way they came out. Lubricate the bearings with a light machine oil, making sure that the bearing surface on the armature is not scored and/or burred up too much. If there is scoring or burring you may need to replace the motor (or machine the armature bearings and replace the bearing inserts - not too easy).
