Can High Voltage tests and DC Bias test run at the same time?
In summary, Hi-Pot yes, SURGE no
Hi-Pot testing with the DC1000:
The DC1000 is connected in parallel with one winding.
As long as the DC1000 is connected to the 'Low' terminal for a HiPot test there will be no issue. Connecting that winding to the 'hi' terminal by accident will simply test the isolation of the DC1000 and is not recommended.
SURGE testing with the DC1000:
Surge testing applies a high voltage to one winding which, through normal transformer action, applies a high voltage to every winding. For this reason the DC1000 should not be connected during surge testing.
In general, high levels of DC bias are applied to transformers constructed using relatively few turns of large gauge wire or foil. The surge test is designed to detect winding insulation faults in transformers constructed of large numbers of turns of very fine wire. It is unusual to require both Hi-Pot and DC current tests for the same transformer.