TROUBLESHOOTING
Service Manual M4 - M10
11.07.2002
Page
50
7.3 Troubleshooting for a defective unit
7.3.1 Warnings
Unit contains live exposed parts, which can be touched, if cover or shield has
been removed.
Before any service measures, make sure power has been disconnected from
each direction it may enter into the drive. Wait until panel has gone blank and
cooling fans are stopped. Before opening the cover of the drive, wait
additional 5 minutes to let remaining energy to be discharged from the DC
capacitors.
NOTE! If you are not aware of safety regulations, basic procedures for safe
working do not enter to phase of failure tracking, where unit is powered up.
7.3.2 Checking instructions
7.3.2.1 Checking of current measurement circuit
Units in power range
CX2 and CXL2 up to 55 kW
CX4 and CXL4 up to 90 kW
CX5 and CXL5 up to 90 kW
CX6 up to 75 kW
Passive checking:
While unit unpowered, check resistance values of shunt resistors on Adapter
boards (CB00005 - CB00009). For location of the shunt resistors (R4...R9), look
at layout drawing of the particular type of the board in section PC BOARDS.
Functional checking:
While the unit is powered up, but not running, measure voltage level from
connector X2, pins -6, -7, -8 on Control board to (DC-). Reference (DC-) can be
found from base plate of voltage regulator A4 on the Control board.
Signal level cross the pins 6 (U), 7 (V), and 8 (W) to (DC-) should be 0V. If level
of output signal variates from zero, internal failure of current transducer (CT)
can suspected to be a reason for malfunction.
Current signals from the CTs and operation voltages for the CTs can be
measured also from Adapter boards.
Units equipped with chassis mounted CTs (M6, M7), input power +/-15V can be
measured from terminals of the wire harness for the CT. Common for the +/-
15V operation voltages and current signals can be found from the connector