Baker D30R, User'S Manual & Operating Instructions

Page: 94 / 142

D30R Users Manual
94
Do Not Touch Test Leads while test is in Progress!
71-023 Rev C 5/8/2007
Armatures
There are two methods of surge testing armatures: the Bar-to-Bar surge test and
the Span surge test. The use of a Footswitch is highly recommended to ease the
operation of these tests.
Bar-to-Bar Surge Test
Bar-to-Bar armature surge testing is the most effective method to test DC
armatures and detect winding insulation weaknesses and faults. In many cases,
where the impedance of the coils in the armature is very low, it may be the only
method possible to test the armature.
To perform bar-to-bar Surge testing, the Model AT101D Bar-to-Bar testing
accessory is necessary. Bar-to-Bar testing instructions accompany the AT101D
and can be found in Supplement 3: Model AT101D Bar-to-Bar Armature Test
Accessory in this manual.
Span Testing
This method uses the brushes of the assembled DC motor to make the
connections with the commutator for testing of the armature. Any number of
bars can be used in this test. Either adjacent bars can be surge tested or a
specific number, or “span” of bars can be tested. The number of bars tested in
each span for an individual motor must be the same during the entire test. In the
repair shop, a fixture can be used in place of the motor’s brushes (refer to Notes
and Tips for Span testing an armature).
Fig 8-4: Span Test using the Motors Brushes