Tony Bird
Senior Member
Hi,
I recently finished making a PMR Dynamo which is fairly simple to make and a good project for someone new to machining castings. In the UK the PMR Dynamo kit consists of two sheets of drawings, two aluminium castings, two magnets, one cast iron casting, an armature and a bag containing screws, brushes and the rest of the materials to complete the model. The cost was £42.
Box of bits.
The cast iron body was machined first.
Bored for magnets.
Not on the drawings but part of the cast iron body's base was machined away.
The mating faces of the aluminium end caps were first finished by hand. Then drilled and mounted in the lathe.
A register was turned on the end cap and the bearing fitted.
On the end cap that holds the brush gear the screw holes for the bushes needed to be spot faced inside the casting. This looked a little awkward to do so to give clearance the inside of the casting was machined away.
Trial assembly.
PMR's castings are very good but the screws supplied aren't! Being in the UK and not having American size taps I had to change the screws anyway.
Instead of using screws studs and nuts were used.
Because I didn't like the vertical orientation of the terminals the magnets were moved 90 degrees and held in place with a screw instead of the lifting ring, this allowed the terminals to be horizontal.
The dynamo works well as a motor so I hope it will generate well. I intend it to be coupled to a Stuart 10H that I have.
Regards Tony.
I recently finished making a PMR Dynamo which is fairly simple to make and a good project for someone new to machining castings. In the UK the PMR Dynamo kit consists of two sheets of drawings, two aluminium castings, two magnets, one cast iron casting, an armature and a bag containing screws, brushes and the rest of the materials to complete the model. The cost was £42.
Box of bits.
The cast iron body was machined first.
Bored for magnets.
Not on the drawings but part of the cast iron body's base was machined away.
The mating faces of the aluminium end caps were first finished by hand. Then drilled and mounted in the lathe.
A register was turned on the end cap and the bearing fitted.
On the end cap that holds the brush gear the screw holes for the bushes needed to be spot faced inside the casting. This looked a little awkward to do so to give clearance the inside of the casting was machined away.
Trial assembly.
PMR's castings are very good but the screws supplied aren't! Being in the UK and not having American size taps I had to change the screws anyway.
Instead of using screws studs and nuts were used.
Because I didn't like the vertical orientation of the terminals the magnets were moved 90 degrees and held in place with a screw instead of the lifting ring, this allowed the terminals to be horizontal.
The dynamo works well as a motor so I hope it will generate well. I intend it to be coupled to a Stuart 10H that I have.
Regards Tony.
