Danfoss Turbocor TTS Series Service Manual page 25

Table 1-3 Expected DC Bus Voltage
1.10.2.1 DC Bus Test Harness Installation for Open-Top Soft Starts
Figure 1-17 J8 Soft Start Connection (Open Top)
8. Reapply AC power to the Compressor.
9. Using an appropriately-rated voltmeter with the 1000VDC range selected, insert the positive
voltmeter lead into the DC (+F) test harness lead, and the negative voltmeter lead into the DC
(-) test harness lead. If the voltage corresponds to "Table 1-3 Expected DC Bus Voltage", the DC
bus voltage is correct and HV DC (F1) fuse on the Soft Start is intact. This would imply that the
Soft Start and Silicon-Controlled Recifiers (SCRs) are functioning correctly; proceed to Step 12.
If voltage reads 0, go to Step 10.
Compressor Nameplate AC
Voltage
575 VAC
460 VAC
400 VAC
380 VAC
10. Leaving the DC(-) test lead in place, relocate the positive (+) test lead to DC(+). If DC voltage is
consistent with "Table 1-3 Expected DC Bus Voltage", this would imply that the Soft Start and
SCRs are working correctly, but the HV DC fuse (F1) on the Soft Start is an open circuit, refer to
"4.25 High Voltage DC-DC Converter" on page 201 to verify the DC-DC Converter.
11. If the DC voltage is not present or is not consistent with "Table 1-3 Expected DC Bus Voltage",
the incoming AC voltage should be verified to be between the acceptable AC Voltage Range
listed in "Table 1-3 Expected DC Bus Voltage". Additionally the F2, F3, F4, F5, and F6 fuses
need to be verified as well as the SCR Diodes and SCR Gates. Refer to "4.19 Silicone-Controlled
Rectifier" on page 133 for testing details.
12. Reset multimeter scaling to read 15VAC and connect to the 15VAC leads of the DC Bus Test
Harness. If the reading is zero, isolate the three-phase supply in accordance with "1.8 Electrical
Isolation" on page 19. When access is safe, remove the four (4) fasteners that hold the Soft
Start in position, and check fuses F2, F3, F4, F5, & F6 for continuity. If any fuse is found to be an
open circuit, replace it and return to Step 6.
13. If the 15VAC is not present, replace the Soft Start (refer to "4.15.3 Soft Start Removal and
Installation" on page 112). If the 15VAC is correct, proceed to the next step.
14. When finished, remove the DC Bus Test Harness. Refer to Section 5 – Removal of the DC Bus
Test Harness.
The DC bus test harness is not designed to be left in the compressor during normal operation. When checks are complete, discon-
nect and remove the test harness.
1. Disconnect the J8 connector from the Soft Start. Refer to "Figure 1-17 J8 Soft Start Connection
(Open Top)".
J8
2. Connect the plug of the compressor cable harness into the corresponding socket of the DC
bus test harness. Refer to "Figure 1-18 Connect DC Bus Test Harness (Open-Top Soft Start)" and
"Figure 1-19 DC Bus Test Harness Connection Diagram (Open-Top Soft Start)" for this and the
following step.
3. Connect the plug of the DC bus test harness into the Soft Start.
Acceptable AC Voltage Range
518-632 VAC
414-506 VAC
360-440 VAC
342-418 VAC
• • • DANGER • • •
Expected DC Bus Voltage Range
700-853 VDC
559-683 VDC
486-594 VDC
462-564 VDC
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M-SV-001-EN Rev. G