TM11-6125-256-34
c Motor Stator
side of diode CR24 (4B48-6-A) or red shunt
field lead disconnected from terminal 5
(1) Remove the dc brush access covers
(4B93-1-A). Resistance should be between
2.628 and 3.212 ohms.
(2) Disconnect shunt field return lead at ground
(7) On PU-750()/A only, check diodes
brush and the two leads at the positive brush
CR24 and CR25 by measuring forward and
reverse resistances.
(3) Check that the contacts of current relay
assembly SW1 are open Closed contacts will give false
NOTE
resistance readings If necessary, disconnect leads
It is not necessary to reconnect leads since
further disassembly is required
(positive input terminal to high side of capacitor C12) I f
necessary, disconnect leads from current relay assembly
SW1 Resistance should be between 0 01188 and 0 01452
ohm
(5) Measure resistance across interpole field (high
side of capacitor C12 to large terminal lead disconnected
from positive brush) If necessary, disconnect leads from
(1) If necessary, use fig. 4-1 or 4-2.
current relay assembly SW1 REsistance should be
as an aid in making continuity measurement
between 0 002250 and 0 002750 ohm
(2) If it is necessary to check the electrical
components within the control box assembly, refer to
(6) Measure resistance across shunt field (shunt
Section V for electrical test values
field lead disconnected from ground brush to negative
4-2
