Carrier D2-3466-2 instruction manual Checking the Power Modules and Motor with Input Power Off

6.3Checking the Power Modules and Motor with Input Power Off

Use the following procedure to check the drive’s Power Module circuitry with power off:

ATTENTION: DC bus capacitors retain hazardous voltages after input power has been disconnected. After disconnecting input power, wait five

!(5) minutes for the DC bus capacitors to discharge and then check the voltage with a voltmeter to ensure the DC bus capacitors are discharged before touching any internal components. Failure to observe this precaution could result in severe bodily injury or loss of life.

Step 1. Turn off and lock out input power. Wait five minutes.

Step 2. Verify that there is no voltage at the drive’s input power terminals.

Step 3. Check the DC bus potential with a voltmeter as described in section 6.2 to ensure that the DC bus capacitors are discharged.

Step 4. Disconnect the motor from the drive.

Step 5. Check all AC line and DC bus fuses.

Step 6. If a fuse is open, use a multimeter to check the input diodes and output IGBTs. See table 6.1.

Step 7. Check motor impedance.

Step 8. Reconnect the motor to the drive.

Step 9. Reapply input power.

6-4 Carrier VFD Quick Reference