Performing Visual Inspections; Conducting Forward And Reverse Biased Diode Tests For Major Power Components - Allen-Bradley PowerFlex 700H Hardware Service Manual

2-4 Component Test Procedures

Performing Visual Inspections

Conducting Forward and
Reverse Biased Diode Tests
for Major Power Components
Visually inspect the cooling tunnels and power structures before energizing
the drive.
Inspecting the Cooling Tunnels
1. Remove the main cooling fans from the bottom of the power structures.
Refer to
2. Inspect the tunnels. Clean the heatsinks and tunnels if necessary.
Inspecting the Power Structures
1. Remove the covers from the power structures. Refer to
Covers from the Power Structures on page
2. Check components for burn marks, breakage or foil delamination on
circuit boards. Check all the boards on the power structures, including
those on the Output Power Modules and the Rectifying Modules (if
present).
Replace any of these components without further testing if they show
evidence of burn marks, breakage or foil delamination.
A forward biased diode test checks the semiconductor junctions between
the terminals and measures the voltage drop across those junctions. To pass
each test, the meter must display a voltage near 0.5V. If the test finds a
short, the meter will display ".000." If the test finds an open circuit or
reversed polarity, the meter will display ".0L" (zero load).
A reverse biased diode test should find an open circuit, and the meter should
display ".0L" (zero load).
~0.5V
+
Forward biased test
on PN-junction
Removing the Main Fans on page
-
3-26.
Removing the
3-15.
+
~.0L
-
Reverse biased test
on PN-junction