Baker D30R, Руководство пользователя

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Surge Test Applications
12/3/2009 | 71-022 V6
D30R 57
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.
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.
Span Test using the motor’s brushes
The wave pattern produced in this test represents the voltage oscillation between the tester
and the coils for the specific number of commutator bars spanned. For example, any 10 bars
spanned in series on the armature should give the same pattern as any other 10 bars
spanned. As the armature is rotated, all the commutator segments and therefore their
respective coils, pass into the “test area” between the hot surge test lead and the GRD lead.
Note:
It is important that the same number of bars (and therefore coils) always be in the
“test area”. The test wave pattern for each span should match a reference wave pattern on
the display for the complete armature if the coils are all good.
1)
Remove all brush pig tail connections from the leads at the brush rigging for all sets of
brushes to isolate the armature from the power source.
2)
Place the tester leads in a grounded position. Connect test lead #1 to one of the brush
assembly pigtails. Connect the GRD test lead to the shaft or other good ground on the
frame.
CAUTION: When testing armatures that have bars that are wired in series, it is very
important to ground at least two bars of the armature a few bars away from those
that are being surged. If this is not done, very high potential voltages to ground can develop in
the armature due to a transformer effect in the coil.
3)
Select the adjacent set of brushes or the brushes of the bar corresponding to the desired
span. Connect test lead #2 and #3 to the pigtail of that brush assembly.
4)
Select the TLS position #1. Be sure the Function switch is set to Surge.
Fig 8-4: Span test setup