Dnepr MT9 - Checking the Generator for Proper Operation; Checking the Generator in the Motor Duty

Checking the Generator for Proper Operation
The proper operation of the generator should be checked on a spe-
cial benc
h:
in the motor dutv;
during idling; -
under load.
In a
ll checks, where application of vo ltage is required, strictly
observe the polarity of
co nnectio n, i. e. connect o nl y a plu~ wire to
terminal "H".
Checking· the Generator in the Motor Duty
Th e generator should be checked for mechanical and electrical
faults in the following order:
tLt;-n the armature by hand to ch ec k it fo r free rotation;
remove the protective band, secure
the generator in a holding
device on the bench and make connections as shown in
the diagram
Fig. 35. Gen era lor
diagram
Fig. 36. Diagr am
sh owing 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);
usi
ng 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 rheo stat,
a ll ow lhe generator to develop
the
mw-;imum no-lo ad speed
atiCl check the intensity of
intensity mu
st be fairly small if
measure the cu rrent consumed by the generator.
If the current consumed is above 6 A, this may be caused bv
mechanical faults, by turn-to-turn short circuit or short circu it s ii1
the arm ature windings or field winding;
check the field coil
\\·inding for good condition by measuring its
resistance with an ohmmeter. Th e resistance must be equal to
2.28 ± 0.12 Q, if the generator is in good condition;
check the field coil
winding for short circuit to frame. For this
purpose
di sconnect the co il lead from the frame and then apply a
voltage from the stor
age battery or mains to output termin al "Ill"
and generator frame. Th e filament of the lamp connected into the
circuit must not glow.
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