Rockwell Automation SB3000 AC Power Modules - Manual (Page 40)

4-2 SB3000 Power Modules (Rittal)
4.2 Power Module Tests with Input Power Off
Use the following procedure to perform the SB3000 Power Module tests:
Step 1. Turn off and lock out AC input power.
Step 2. Wait ten minutes to allow the DC bus voltage to dissipate.
Step 3. Look at the built-in DC Bus Voltage meter. When the DC bus potential is
down to approximately zero volts, open the SB3000 Power Module cabinet's
doors and measure the DC bus potential across the DC bus bars, 1247A
(+ bus) and 1145A (- bus), with an external voltmeter before working on the
unit. See figure 4.1.
Step 4. Check the AC input and DC bus output fuses.
Step 5. If a fuse is blown, use a multimeter to check the DC bus, bus capacitors, AC
input terminals, and the input IGBTs. See tables 4.1 and 4.2.
Step 6. If a capacitor is defective, replace the capacitor bank assembly as described
in section 4.5.4. If an IGBT is defective, refer to section 4.5.2.
!
ATTENTION: The Power Module is not isolated from earth ground. The
test instruments used to measure Power Module signals must be isolated
from ground through an isolation transformer. This is not necessary for
battery-powered test instruments. Failure to observe this precaution
could result in bodily injury.
ATTENTION: If a megohmmeter (megger) is used to verify an
inadvertent ground internal to the motor, make certain that all leads are
disconnected between the rotating equipment and the Power Module
cabinet. This will prevent damage to electronic circuitry (Power Modules
and their associated circuitry) due to the high voltage generated by the
megger. Failure to observe this precaution could result in damage to or
destruction of the equipment.
!
ATTENTION: DC bus capacitors retain hazardous voltages after input
power has been disconnected. After disconnecting input power, wait ten
(10) minutes for the DC bus capacitors to discharge, then look at the
built-in DC bus voltage meter. When the voltage is down to approximately
zero (0) volts, open the cabinet doors and check the voltage across the
DC bus bars, 1247 A,B,C (+ bus) and 1145 A,B,C (- bus), with an external
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.