Checking The Generator For Proper Operation; Checking The Generator In The Motor Duty - Dnepr MT9 Repair Manual

Checking the Generator for Proper Operation
The prop er operation of the generator should be checked on a spe-
cia l bench:
in the motor dutv;
during idling; -
under load.
In all checks, where application of vo ltage is required, strictl y
observe the polarity of co nn ectio n, i.e. connect onl y a
plu~
wire t o
terminal
"H".
Checking· the Generator in the Motor Duty
Th e generator should be checke d for mechanical and e lectrical
faults in the following order:
tLt;-n the a rmature by hand to chec k it fo r free rotation;
remove the protective band, secure the generator in a holdin g
device on the bench and make connections as shown in the diagram
Fig. 35. Gen era lor
diagram
Fig. 36. Diagram
s howing lhe con-
nection of genern ·
tor for testing un-
der motor duly
conditions
spnrking under the brushes, which
the generator is in good condition;
(Fig. 36);
us ing the rheostat, adjust
th e rotative speed of the arma-
ture ior n=200 to 250 r.p.m.
Check the armature for smooth
rotation. Non-uniform rotation
indicates that the armature
winding or commutator sheets
arc at fault;
by cutting out th e rheostat,
all ow lhe genera tor to develop
the mw-;imum no-lo ad speed
atiCl check the intensity of
intens ity mu st be fairly small if
measure the cu rrent consumed by the generator.
If the current consumed is above 6 A, thi s may be caused bv
mechanical faults, by turn-to-turn sho rt circuit or short circu its ii1
the armature windings or field winding;
check the field coil \\·indin g for good condition by measuring its
resistance with an ohmmeter. The resistance must be equal to
2.28 ± 0.12
Q,
if the generator is in good condition;
check th e field coil winding for short circuit to frame. For thi s
purpose di sconnect the coil lead from the frame an d then apply a
voltage from the storage battery or main s to output termin al "Ill"
and generator frame. Th e filament of the lamp connected into th e
circuit must not glow.
106