The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => Lucas, Ignition, Charging, Electrical => Topic started by: v8ivor on 06.03. 2016 17:58

Title: Dynamo commutator end bearing
Post by: v8ivor on 06.03. 2016 17:58

Hi again,
Can anyone tell me what way round and where this top hat washer goes ? And should I put the bearing onto the armature before pressing the bearing end bracket on ? Only there is nothing to tell me the position of the bearing in the end bracket.
Thank you once again,
Ivor.

Title: Re: Dynamo commutator end bearing
Post by: beezermacc on 06.03. 2016 20:11

The purpose of this washer is to hold the felt grease seal against the bearing so the grease doesn't escape from the bearing. If you are using sealed bearings this item is redundant. There is a small sleeve which fits over the shaft against the commutator, then this dished washer with the raised centre towards the bearing, the felt seal next, then the bearing. On the outside of the bearing there is another felt, a washer then a screw in the end of the armature shaft. However, if you are using sealed bearings you only need the sleeve and the bearing. It could be argued you don't need the sleeve either, as long as the bearing doesn't slide down the shaft when you're fitting it in its housing.

Title: Re: Dynamo commutator end bearing
Post by: trevinoz on 06.03. 2016 20:13

That washer is not necessary if you  use sealed bearings, it is the felt washer retainer.
However, I put it back, large diameter towards the comm, to maintain the bearing in the correct position for the securing screw to bear against the inner race. If your armature is the later type with the wire circlip the bearing will be right at the groove.
The bearing has to be fitted to the armature first, end shield pushed on.

Title: Re: Dynamo commutator end bearing
Post by: v8ivor on 06.03. 2016 21:23

Thanks Trevor and Beezer,
I could cut a felt washer out for that side but the end of the armature that protrudes past the bearing has been machined off, leaving no thread for a retaining screw for an outer seal, so it's looking like a new sealed bearing is the way to go. Also there is no grove for retaining/stop for the outer race, so I will put the bearing on the commutator and the press the end shield home.
Ivor.

Title: Re: Dynamo commutator end bearing
Post by: beezermacc on 07.03. 2016 07:33

I stock all the parts you need just in case you're stuck for anything.