Service manual

T r o u b l e s h o o T i n g T r e e s • C o m b i t h e r m C t e x p r e s s t e C h n i C a l s e r v i C e m a n u a l • D – 19
troubleshooting trees
Single Speed Motor - No Motor Operation (with motor protection switch)
Is there L1 power
supplied to terminal 21 of
K-52 contactor?
Is there L1 power at
terminal 22 of K-52 contactor?
L1 supplied to terminal
21 from RBH/X3/300
No
Yes
Yes
No
Yes
Is K-52 coil energized
and engaged?
Yes
Yes
Yes
Yes
Yes
Yes
No
No
No
No
No
No
No
Repair wiring between
K-52/22 and F-51/2
Repair wiring between
F-51/43 and motor
L2/43 supplied from N-7
High limit
Repair motor wiring
Ohm out motor and replace
if necessary
Is L1 power at terminal 2
of F-51?
Is L1 power at terminal 5
of F-51?
Is L1 power at blue wire
on motor?
Is L2 power at terminal
43 of F-51?
Is there voltage across
blue/white wires at motor?
Is motor running?
Motor is operating correctly
Replace faulty K-52
contactor
No
Yes
Unit is in low speed
operation
Repair/replace F-51 MPS
Yes
No
Is F-51 motor
protection switch (MPS) in
the start position?
Reset switch and
test operation
Is L2 power at white wire
on motor?
Repair wiring between
F-51/5 and motor