physically damaged capacitor, if suspect, the entire
capacitor bank must be replaced. Replace the capacitor
bank in accordance with the disassembly procedures in
7 D-Frame Sizes Disassembly and Assembly Instructions
or
8 E-Frame Sizes Disassembly and Assembly Instructions
.
6.2.4 Heatsink Temperature Sensor Test
The temperature sensor is an NTC (negative temperature
coefficient) device. As a result, high resistance means low
temperature. As temperature decreases, resistance
increases. Each IGBT module has a temperature sensor
mounted internally. The sensor is wired from the IGBT
module to the gate drive card connector MK100. For filters
with two IGBTs, the sensor on the right module is used.
For filters with three IGBT modules, the center module is
used.
On the gate drive card, the resistance signal is converted
to a frequency signal. The frequency signal is sent to the
power card for processing. The temperature data is used to
regulate fan speed and to monitor for over and under
temperature conditions.
1.
Use ohmmeter set to read ohms.
2.
Unplug connector MK100 on the gate drive card
and measure the resistance across the cable
leads.
The relationship between temperature and resistance is
nonlinear. At 77° F [25° C], the resistance will be approxi-
mately 5 k Ω. At 32° F [0
°
C], the resistance will be
approximately 13.7 k Ω. At 140° F [60
°
C], the resistance
will be approximately 1.5 k Ω. The higher the temperature,
the lower the resistance.
6.2.5 Fan Continuity Tests
Make all continuity checks using an ohmmeter set to Rx1
scale. A digital or analog ohmmeter can be used. Some
instability may result when measuring resistance of a
transformer with a multimeter. This can be reduced by
turning off the auto-ranging function and setting the
measurement manually.
To aid in making the measurements, unplug the MK107
from the power card.
Checking continuity of connections
For the following tests, read connector MK107 on the
power card.
1.
Measure from L3 (T) to MK107 terminal 16.
Reading of <1 Ω should be indicated.
2.
Measure from L2 (S) to MK107 terminal 1.
Reading of <1 Ω should be indicated.
Incorrect reading
An incorrect reading would indicate a faulty cable
connection. Replace the cable assembly.
6.2.5.1 Fan Fuse Test
1.
Test the fan fuses on the soft charge mounting
plate by checking the continuity across the fuse.
An open fuse could indicate additional faults. Replace the
fuse and continue the fan checks.
6.2.5.2 Ohm Test of Transformer
For the following tests, read the plug end of the wire
connected to MK107 on the power card.
1.
Measure between MK107 terminals 1 and 16.
Should read approximately 4 Ω.
2.
Measure between MK107 terminals 16 and 12.
Should read approximately 3 Ω.
3.
Measure between MK107 terminals 1 and 12.
Should read approximately 1 Ω.
Incorrect reading
An incorrect reading would indicate a defective fan
transformer. Replace the fan transformer.
When finished, reconnect the MK107.
6.2.5.3 Ohm Test of Fans
Ohm test of fans Measure between terminals 11 and 13 of
power card connector MK107.
Incorrect reading
Disconnect CN5 and measure the resistance between pins
1 and 2 on the fan side of the connector. Reading should
be approximately 4 Ω. If incorrect, replace fan F2.
Disconnect CN4. Measure the resistance across 1 and 2 on
the fan side. Reading should be approximately 200 Ω.
Incorrect reading
Isolate the faulty fan as follows.
a.
Disconnect the wiring from the fan terminals.
b.
Read across the fan terminals on each fan. A
reading of 400 Ω is expected. Replace any
defective fans.
Test Procedures
VLT Advanced Active Filter AAF006 D and E Frames Service Manual
6-4
MG90Z122 - VLT
®
is a registered Danfoss trademark
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