Needs Pictures: 0
Results 16 to 24 of 24
-
24th Aug 2021, 02:13 PM #16Senior Member
- Join Date
- Oct 2015
- Location
- melbourne
- Posts
- 473
The lms ones are close, but with shipping and conversion to aud, comes in at nearly $40.
I spoke to a lovely lady at Schunk in Melbourne who have a good range, she identified some i could probably modify ok. ($25)Or they can also custom manufacture, but @ $40 (plus tax) (each) i will keep looking for candidates to modify.
I have found in my stash an old ducted vacuum motor with brushes just about wide enough i should be able to file down.
(ive also been looking at various other devices; it seems to me that often they are installed in a metal tube which would also serve to connect the brush in addition to the spring)
-
25th Aug 2021, 10:53 AM #17Most Valued Member
- Join Date
- Mar 2011
- Location
- Southern Flinders Ranges
- Posts
- 1,536
To go off on a tangent for a moment..
The DC fuelled locomotives at work have a length of 1 1/4” x1/4” copper braid connecting them to the primary traction bus, using 5/8 bolts torqued to some ridiculous level that requires the use of a hydraulic nut spinner. The brushes themselves are about 4”x2” and there are several brushes common to each other around the perimeter.
Back to scheduled program
-
25th Aug 2021, 12:45 PM #18Senior Member
- Join Date
- Apr 2018
- Location
- Perth
- Posts
- 168
-
25th Aug 2021, 06:00 PM #19
Hi Adam, Guys,
Like this one photographed in the "Blists Hill" village museum near Telford in the Midlands, UK.
29-01-2019-055.jpg
You can see the four rows of four brushes round the commutator.Best Regards:
Baron J.
-
27th Aug 2021, 09:30 PM #20Senior Member
- Join Date
- Oct 2015
- Location
- melbourne
- Posts
- 473
The donor
20210826_203659.jpg
The outcome, after a bit of filing.
20210826_203433.jpg
I'll try it out tomorrow. What could go wrong?
-
27th Aug 2021, 11:38 PM #21
Hi Russ,
I notice that you have left a step on the sides ! Bad idea, those steps will cause the brush to arc onto the next segment of the commutator.
I don't file my replacements, I use a belt sander and then a sanding stick (sandpaper glued to a piece of wood) to finish them off to size.Best Regards:
Baron J.
-
28th Aug 2021, 11:48 AM #22Senior Member
- Join Date
- Oct 2015
- Location
- melbourne
- Posts
- 473
Thanks for the advice baron
I left the step because it is only just wide enough. I figured that would help keep it centred and prevent rotation.
In normal operation, there is a brief time where two segments are in contact as a typical brush is much wider than the gap between the segments.
I'll only replace the one faulty one, so even if it does contact the adjacent commutator segment for longer, the same won't happen on the opposite side so shouldn't get any extra current flow.
I will smooth the end off a bit, and will check for any sign of arcing after a few minutes running.
(this brush seemed pretty soft - i reckon it would disappear on a belt sander...
(and i am still looking for a better match brush)
-
28th Aug 2021, 11:58 AM #23Senior Member
- Join Date
- Apr 2018
- Location
- Perth
- Posts
- 168
-
28th Aug 2021, 07:38 PM #24
Hi Russ, Guys,
Some brushes are much harder than others. The ones that I'm using and cutting up are much harder than the original ones.
Its basically a balance between brush and commutator wear. Strong springs and a hard brush will last longer but will wear the commutator more. In my case the brush is about 5 mm longer than the original and the spring is more compressed, theoretically giving me a better conductivity between the spring and brush. I did experiment with turning a little boss on the end of the brush for the spring to grab onto, but found that it didn't make any measurable difference to the resistivity of the assembly.
Sparksy: Yes I do wear a dust mask when sanding the brush material, I also try to do it outside as well.
Its a good idea to wear vinal gloves as well, the dust gets into your skin and its a right pain to wash off.Best Regards:
Baron J.
Similar Threads
-
Collets for lathe work
By morrisman in forum METALWORK GENERALReplies: 35Last Post: 13th May 2013, 01:48 AM -
RFQ: Lathe Work And Mill Work
By twistedfuse in forum METALWORK GENERALReplies: 4Last Post: 18th Jan 2012, 04:23 PM -
Can I get Custom Lathe Work Done?
By mattaus in forum METALWORK GENERALReplies: 21Last Post: 25th Aug 2011, 01:55 PM -
Replying doesn't work?
By Ziapurple in forum FORUMS INFO, HELP, DISCUSSION & FEEDBACKReplies: 5Last Post: 30th Mar 2009, 02:40 PM