Great!
I've just come across a bit of general information regarding brush pressure since posting the thread from the Little Red Book published by Brook-Hansen, official title 'Installation & Maintenance of Electric Motors' If anyone is interested it's an excellent reference book.
It states that 'as a general rule the brush spring pressure should be 0.2Kg per square cm for speeds up to 2,500rpm and 0.25Kg per square cm at higher speeds.
So. Size of my brushes are 10mm by 5mm, that is, one cm. by a half cm. making the area one half of a square centimetre. As the speed is the same as the engine speed then it will be way over 2,500rpm so the pressure should be 0.25 x 0.5 = 0.125Kg i.e. 125gms or four and a half ounces.
Anyway, after all the calculations it wouldn't be easy to measure in my case. One whole turn will do me fine, Grant.
Many thanks
John
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Johnef
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