13. Q. Is it advisable to ever try to fit a brush with a file or knife?

A. Most emphatically no. You could not get a bearing across the brush no

matter how hard you might try with either a file or a knife.

14. Q. Why is it important to clean the scale off of the point of the

copper electrode each trip?

A. The scale on the copper electrode after it has cooled off is a

non-conductor of current, and acts as a blind gasket between the carbon

and the copper electrode. Unless this scale is removed, the current

cannot pass between the points of carbon and electrode and you cannot,

therefore, have a light. When the dynamo fields are compound wound, it

is unnecessary to clean scale from copper electrode oftener than once a

week, at which time copper electrode should be removed from holder and

all scale cleaned off. (With compound wound dynamo fields the cab lamps

will continue to burn when head-lamp is extinguished by lifting carbon

by hand.)

The Traveling Engineers' Association to Improve the Locomotive Engine Service of American Railroads Examination Questions and Answers for Firemen for Promotion and New Men for Employment · 第 232 / 436 题