Intermediate Section Tests; Location Of Udc Terminals - Trane TR150 Service Manual

Test Procedures

6.3.4 Intermediate Section Tests

NOTICE
This test is applicable for H7, H8, I7, and I8 units only.
The intermediate section of the frequency converter is
made up of the DC bus capacitors, the DC coils, and the
balance circuit for the capacitors.
1. Test for short circuits with the ohmmeter set on
Rx100 scale or, for a digital meter, select diode.
2. Measure across the positive (+) DC terminal and
the negative (–) DC terminal. Observe the meter
polarity.
3. The meter starts out with low ohms and then
move towards infinity as the meter charges the
capacitors.
4. Reverse meter leads.
5. The meter pegs at zero while the meter
discharges the capacitors. The meter then begins
moving slowly toward 2 diode drops as the meter
charges the capacitors in the reverse direction.
Although the test does not ensure that the
capacitors are fully functional, it ensures that no
short circuits exist in the DC link.
Incorrect reading
A short circuit could be caused by a short in the inrush
circuit, rectifier, or inverter section. Be sure that the tests
for these circuits have already been performed successfully.
A failure in one of these sections could be read in the
intermediate section since they are all routed via the DC
bus.
The only other likely cause would be a defective capacitor
within the capacitor bank.
There is not an effective test of the capacitor bank when it
is fully assembled. If suspecting a failure within the
capacitor bank, replace the entire bank. Replace the
capacitor bank in accordance with the disassembly
procedures.
BAS-SVM04B-EN
TR150 and TR170 Service Manual

6.3.5 Location of UDC Terminals

H6
Remove the IP20 front cover, then remove the capacitor
vibration support. The terminals K601 (+UDC) and K611 (-
UDC) are located between the 4 capacitors on the circuit
board. Remove the metal cover to access these terminals.
Illustration 6.5 UDC Terminals Location on H6 Frequency
Converter
Illustration 6.6 Metal Cover over Terminals
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