GE Industrial Solutions AF-600 FP High Power (460V_575V 150HP and above) - Manual (Page 82)

6.2.8 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 frequency converters with two IGBTs, the sensor on the right module is used. For frequency converters with three IGBT modules, the centre 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 undertemperature conditions.
1. Use ohmmeter set to read ohms.
2. Unplug connector MK100 on the gate drive card (see Illustration 6-17) and measure the resistance across the cable leads.
The relationship between temperature and resistance is nonlinear. At 25°C, the resistance will be approximately 5k Ohms. At 0 ° C, the resistance will be approx-
imately 13.7k Ohms. At 60 ° C, the resistance will be approximately 1.5k Ohms. The higher the temperature, the lower the resistance.
6.2.9 Fan Continuity Tests: 4x-frame size
Make all continuity checks using an ohmmeter set to Rx1 scale. Digital or analog ohmmeter can be used.
To aid in making the measurements, unplug the connector CN2 from its mate. CN2 terminals correspond to the terminal numbers labelled on the transformer.
Connector CN2 is located near the fan transformer on the input plate. See Illustration 6.10.
Fan Fuse test
1. Test the fan fuse on the input plate by checking the continuity across the fuse.
An open fuse could indicate additional faults. Replace the fuse and continue the fan checks.
Checking continuity of connections
For the following tests, read the plug end of connector CN2 that is not connected to the transformer.
1. Measure from L3 (T) to CN2 terminal 1. A reading of <1ohm should be indicated.
2. Measure from L2 (S) to CN2 terminal 3. A reading of <1 ohm should be indicated.
3. Measure from CN2 terminal 2 to terminal 12 on the power card connector MK107. A reading of <1 ohm should be indicated.
Incorrect reading
An incorrect reading would indicate a faulty cable connection. Replace the cable assembly.
Ohm test of transformer (380–480V)
For the following tests, read the plug end of connector CN2 that is connected to the transformer.
1. Measure between CN2 terminals 1 and 3. Approximately 15 ohms should be read.
2. Measure between CN2 terminals 1 and 2. Approximately 12 ohms should be read.
3. Measure between CN2 terminals 2 and 3. Approximately 4 ohms should be read.
Incorrect reading
An incorrect reading would indicate a defective fan transformer. Replace the fan transformer.
When finished, be sure to reconnect CN2.
Ohm test of transformer (525–690V)
For the following tests, read the plug end of connector CN2 that is connected to the transformer.
1. Measure between CN2 terminals 1 and 3. Approximately 20 ohms should be read.
2. Measure between CN2 terminals 1 and 2. Approximately 8 ohms should be read.
3. Measure between CN2 terminals 2 and 3. Approximately 12 ohms should be read.
Incorrect reading
An incorrect reading would indicate a defective fan transformer. Replace the fan transformer.
When finished, be sure to reconnect CN2.
AF-650 GP and AF-600 FP High Power Service Manual
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