Inverter Test Part I; Inverter Test Part - Danfoss VLT HVAC Drive FC100 Service Manual

Test Procedures
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7
4, 8, 9
5
6
Illustration 6.6 12-pulse inverter module test points
1 External temperature monitoring
2 Relay 1 (01, 02, 03) and relay 2 (04, 05, 06)
3 NAMUR
4 AUX fan (MK100, MK101, MK102, MK103)
5 Brake terminals 81 (-R), 82 (+R)
6 Motor connections (96 (U), 97 (V), 98 (W)
7 NAMUR fuses
8 Fan fuses
9 SMPS fuses
Before starting tests, ensure that meter is set to diode
scale.
High Power Service Manual for Modular F Frame Drives
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MG90K202 - VLT is a registered Danfoss trademark

6.2.2.2 Inverter test part I

1. Connect the positive (+) meter lead to the (+)
positive DC bus bar.
2. Connect the negative (–) meter lead to terminals
U, V, and W in sequence.
2
1
3
4
5
1 Top (-)DC link fuse bus bar
2 (-)DC link fuse (none in 12-pulse models F8/F9)
3 Top (+)DC link fuse bus bar
4 (+)DC link fuse (none in 12-pulse models F8/F9)
5 Bottom (+)DC link fuse bus bar
Each reading should show infinity. The meter will start at a
low value and slowly climb toward infinity due to
capacitance within the frequency converter being charged
by the meter.
6.2.2.3 Inverter test part II
1. Reverse the meter leads by connecting the
negative (–) meter lead to the positive (+) DC bus
bar.
2. Connect the positive (+) meter lead to U, V, and
W in sequence. Each reading should show a
diode drop.
Incorrect reading
An incorrect reading in any inverter test indicates a failed
IGBT in that inverter module. Replace the IGBT module
according to the disassembly instructions. The inverter
module must be removed to replace the IGBT module.
Inverter test part III
1. Connect the positive (+) meter lead to the
negative (-) DC bus bar.
2. Connect the negative (–) meter lead to terminals
U, V, and W in sequence. Each reading should
show a diode drop.
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