Rockwell Automation Liqui-Flo 1.5 AC Power Modules V1.2 - Manual (Page 55)

Troubleshooting the Drive 9-3
9.4 Checking the Power Modules with Input Power Off
Use the following procedure to check the drive’s Power Module circuitry with power off:
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 9.3 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 9.1.
Step 7. Reconnect the motor to the drive.
Step 8. Reapply input power.
!
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.
Table 9.1 – Resistance Checks
Input
Diode
No.
Meter
Connection
(+) (-)
Component is OK if
resistance (R) is: Component is defective if:
1 * L1 10 < R < 1 megohm Continuity (short circuit) or
open when the meter is
connected with reversed
polarity.
2 * L2
3 * L3
4 * L4
5 * L5
6 * L6
7 L1 **
8 L2 **
9 L3 **
10 L4 **
11 L5 **
12 L6 **
* (+) DC Bus Volts power terminal
** (-) DC Bus Volts power terminal