GENERATOR
M o s t of the g e n e r a t o r s u s e d on the
K662
a r e of the
3
b r u s h , s h u n t wound type DC g e n e r a t o r s f o r
1 2
volt e l e c t r i c a l s y s t e m s . Some e a r l i e r g e n e r a t o r s have hinged o i l e r c a p s and r e q u i r e l u b r i c a t i o n a t
r e g u l a r i n t e r v a l s , although m o s t have s e a l e d b e a r i n g s which d o not r e q u i r e r e g u l a r s e r v i c i n g . On a l l
g e n e r a t o r s , the b r u s h e s and c o m m u t a t o r m u s t be checked a t s p e c i f i c i n t e r v a l s . S e r v i c e g e n e r a t o r s a t
the i n t e r v a l s s t a t e d i n the following s e r v i c e s t e p s .
B r u s h e s
A f t e r e a c h 500 h o u r s of o p e r a t i o n , r e m o v e t h r u
a n d t a k e off end f r a m e to o b s e r v e condition
of b r u s h e s ,
a n d h o l d e r s . R e p l a c e b r u s h e s if
w o r n o r if worn t o l e s s than
t h e i r
o r i g i n a l l e n g t h
l o n g ) . ' R e p l a c e s p r i n g s if c o r r o d e d o r if blued o r d i s c o l o r e d f r o m e x c e s -
s i v e heat.
B r u s h a r m s a n d b r u s h e s m u s t move f r e e l y without tendency t o bind o r c o c k in h o l d e r s .
L
I
FIGURE 7-4
--
TYPICAL DC GENERATOR
DISASSEMBLED VIEW
C o m m u t a t o r
O b s e r v e c o n d i t i o n of the c o m m u t a t o r a t the s a m e t i m e the b r u s h e s a r e s e r v i c e d (500 h o u r s ) .
If
d i r t y , c l e a n with No. 00 S a n d p a p e r . Make s u r e d u s t i s r e m o v e d a f t e r cleaning. If
i s g r o o v e d ,
r o u g h o r out of r o u n d , r e m o v e a r m a t u r e and p l a c e i n l a t h e s o t h a t c o m m u t a t o r c a n b e t u r n e d down.
R e m o v e only enough m a t e r i a l t o m a k e c o m m u t a t o r s m o o t h and round. A f t e r r e s u r f a c i n g , u n d e r c u t the
m i c a i n s u l a t i o n 1 / 3 2 " deep. F i n i s h with No. 00 S a n d p a p e r a f t e r undercutting a n d blow
a l l d u s t .
L u b r i c a t i o n
On g e n e r a t o r having the hinged c a p o i l e r s , add s e v e r a l d r o p s of SAE 20 weight o i l to both c a p s
( a t c o m m u t a t o r a n d d r i v e end f r a m e s ) a f t e r e a c h 200 h o u r s of o p e r a t i o n o r e v e r y f o u r t h oil change
p e r i o d . CAUTION: Do not add too m u c h o i l a s this m a y c a u s e o v e r h e a t i n g of the b e a r i n g . Add only a
few d r o p s a t e a c h s e r v i c e p e r i o d .
B e l t T e n s i o n
O c c a s i o n a l l y c h e c k condition of b e l t a n d a l s o c h e c k b e l t t e n s i o n . B e l t should b e a d j u s t e d s o t h a t
i t d e f l e c t s a b o u t
when d e p r e s s e d with f i n g e r a t midpoint on u p p e r span.
Too l i t t l e t e n s i o n r e s u l t s
i n b e l t s l i p p a g e a n d r a p i d w e a r of the b e l t . E x c e s s i v e t e n s i o n a l s o c a u s e s r a p i d w e a r and c a n d a m a g e
g e n e r a t o r b e a r i n g s .
L o o s e n g e n e r a t o r mounting b r a c k e t and m o v e g e n e r a t o r until p r o p e r t e n s i o n i s
a t t a i n e d .
