©2019 ALL-TEST Pro, LLC All Rights Reserved 47 Rev 06/20/2019
DC Compound Single Voltage Motors
DC Compound single voltage motors normally
have 2 separate field windings. 1 shunt field which
is in parallel with the armature windings and 1
series field, which is in series with the armature
winding. For testing DC compound motors, the
shunt field winding is tested by itself. The series
and armature winding are each tested together as
in a DC series motor.
The armature leads are normally labeled A1 & A2, the field coil leads for the shunt field coil are
normally labeled F1 & F2, and the field coil leads for the series field coil are normally labeled S1
& S2. For the windings to be in series, A2 & S1, or S2 & A1 are connected. Test the series and
armature windings by connecting the AT5™ test leads to free- end on the armature lead and the
free end of the field coil.
It is recommended to take the shunt field winding first, the series field and armature winding 2
second.
Note: Always re-measure the armature windings to look for carbon build up.
Since the Field leads are parallel to the armature windings, separate IRG to ground are taken
from the field coils to Ground or the frame and the armature coils to ground or frame a third
Insulation resistance measurement is taken from the field coil to the armature coil.
INS1 = field windings to ground
INS2 = armature windings to ground
INS3 = field winding to armature winding
STATIC readings for DC Compound Single Voltage Motors
DC1 = Series & Armature Coil
DC2 = Field Coil
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