page 58
Industrial Power Corruptor Manual Rev 1.00
Appendix D - Theory of Operation
The IPC is inserted between an AC power source and Equipment Under Test (EUT).
Power terminals on rear panel:
The power terminals are grouped into "source" and "load" terminals. Each set of terminals can accept up to three (3)
phase conductors, an optional neutral conductor, and a required protective earth conductor. All of the terminals are
internally connected to 0,5 inch bus bars. The three source-side phase terminals pass through current transformers, then
are connected directly to the main circuit breaker. Spring-loaded contacts pick up the source and load voltages. The three
load-side phase terminals also pass through current transformers. Both protective earth terminals are connected directly to
the IPC chassis, and pass through PE current sense transformers. If more than 500mA is detected on either PE terminal, the
panic signal is asserted.
Main circuit breaker:
The main circuit breaker includes three trip mechanisms: a fast magnetic trip, a slow thermal trip, and a shunt trip.
The shunt trip is activated whenever the red front panel Of
f button is pressed, and whenever the Panic signal is asserted for
any reason.
Phase configuration relays:
These sixteen electro-mechanical relays connect the source power terminals and the load power terminals appropriately.
They can bypass the IPC completely, or they can connect any phase, or pair of phases, as inputs or outputs to the sag/swell
generator section. These relays are also used for three-phase interruptions; the operate and release time of each relay is
factory calibrated in flash memory, so precision phase angles can be obtained.
Power up sequence:
The IPC begins by shunt-tripping its main circuit breaker, for safety reasons. Then the Control Processor, which
manages all of the firmware, boots up each of the other four processors, and loads them with their firmware. Finally
, the
Control Processor turns its attention to the front-panel serial port and waits for communication from the IPC program
running on a Windows computer.
Internal communication and control:
In general, each circuit board on the IPC has at least one processor, and each processor has at least one 4-channel serial
communications chip. Serial communications was chosen to maximize reliability and to minimize noise problems. In
addition to the serial communications between processors, three open-collector negative-true signals are routed throughout
the IPC: arm, trigger, and panic. These three signals are available on BNC terminals on the rear of the IPC. The arm signal
is asserted by the Relay Processor prior to performing an event. The trigger signal goes low at the precise beginning of an
event, and returns high at the precise end of an event. The panic signal trips the main circuit breaker through its shunt-trip
mechanism.
Power for the IPC:
Power for the IPC enters an IEC connector at the bottom left of the back panel. It immediately passes through a high-
frequency noise filter
, then progresses by cable to the Power Supply board. The earth connection on this cable passes
through a current transformer; if 500 mA or more is ever detected on the earth conductor, the Power Supply board asserts
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