Chapter 7 – Trouble Shooting & Maintenance
7-9
2) Power Component Check – 50 HP ~ 125 HP
Module
Test polarity
Reading Module
Test polarity
Reading
+ -
+ -
DC Bus
Fuse
Fuse 1 across fuse Closed
Fuse
Indicator
Fuse 1
across
indicator Closed
SCR's
*SCR1
D1
R P2 (+) Open
Diodes
D4
R N (-) Open
P2 (+) R Open N (-) R Closed
SCR2
S P2 (+) Open
D5
S N (-) Open
P2 (+) S Open N (-) S Closed
SCR3
T P2 (+) Open
D6
T N (-) Open
P2 (+) T Open N (-) T Closed
* measurement is across Rpre/D1 (series) in parallel with SCR1
A 125 HP has 6 SCR/Diode modules (SCR1a, SCR2a, D1a, D2a, etc.)
IGBT's
Tr1
U P2 (+) Closed
IGBT's
Tr4
U N (-) Open
P2 (+) U Open N (-) U Closed
Tr3
V P2 (+) Closed
Tr6
V N (-) Open
P2 (+) V Open N (-) V Closed
Tr5
W P2 (+) Closed
Tr2
W N (-) Open
P2 (+) W Open N (-) W Closed