Publication 2364F-5.05 - March 1999
4-14
Testing Components
Testing the DC Bus Suppressor
The DC bus suppressor discharges excess voltage from the DC bus.
1. Push the disconnect lever to off and wait for all voltage to discharge
from the unit. Do not continue until all voltage has dissipated from the
DC bus.
2. Verify that there is no voltage across the DC bus (see Figure 4.12 and
Figure 4.13 for check points).
3. Verify that there is no voltage across the subcomponents of the
suppressor.
4. Check the suppressor and any associated wiring for visible damage (burn
marks or damaged subcomponents).
5. Check the resistance between the top of each capacitor with respect to
the PE terminal. The meter should show 8-10 ohms.
6. Set meter for resistance and test each resistor. The two middle resistors
should read 8.5-9.5 k-ohms (9 k-ohm rating). The two outer resistors
should read 14.7-15.8 ohms (15 ohm rating).
If the suppressor has failed any of the above tests, it may be damaged.
Replace the suppressor and consider replacing any associated wiring, as
necessary.
Figure 4.9
DC Bus Suppressor
PE Connection
15 ohm
Resistors
9 k-ohm
Resistors
