RK3000 High Frequency Power Supply
Operating Manual
Page 56 of 73
Waveform #7, Typical Control Waveform
This typical control waveform shows the action and relation of Phase Back Ramp,
Quench, Pedestal, and Process Sense.
The leading part of this waveform shows the gradual reduction of precipitator current due
to an upset operating condition. When an Arc is encountered, the RK3000 Quenches the
current for a programmed Quench Time, then the Pedestal is initiated and the RK3000
again tries to reach normal operating power levels. A Spark occurs as the RK3000
attempts to increase current and the Phase Back and Ramp go into operation. Sparking
becomes more frequent and occurs at lower and lower power levels. The RK3000
phases back after each Spark to establish a new operating level just below the threshold
of sparking. Note that as the current gets lower, the amount of Phase Back decreases
automatically.
After each Phase Back, the Ramp Rate tries to increase the current level back to
maximum. However, due to existing conditions, another Spark is encountered and the
current phases back again. Notice that the slope of the Ramp Rate automatically
decreases as the current level drops.
If the Process Sense time elapses and a Spark has not occurred, a faster recovery rate
takes over and rapidly increases the current level until either current rating is reached or a
Spark occurs.
Sketch 7: Typical RK3000 Control Operation