Woodward ProTech 203, Руководство по эксплуатации

Страница: 16 / 40

ProTech 203 Overspeed Protection System Manual 85204
10 Woodward
Vibration
US MIL-STD-810D, Method 516.3, Procedure I
Weight
7.3 kg (16 lbs)
Modes of Operation
The ProTech 203 system is offered in de-energize-to-trip versions and energize-
to-trip versions. Two normally open and two normally closed relay contacts are
provided by the system for use in either version. Figure 3-2 shows the relay field
wiring diagram that describes these options.
Figure 3-2. Interposing Relay Field Wiring
In the de-energize-to-trip version, the interposing relay is in its energized state
during normal operation. TB3 terminals 1 and 2 are connected, and TB2
terminals 4 and 5 are connected. During an overspeed trip event, or when power
to the ProTech 203 system is lost, the interposing relay is de-energized. Then
TB3 terminals 2 and 3 are connected, and TB2 terminals 5 and 6 are connected.
In the energize-to-trip version, the interposing relay is in its de-energized state
during normal operation. TB3 terminals 2 and 3 are connected, and TB2
terminals 5 and 6 are connected. Only during an actual overspeed trip event is
the interposing relay energized. Then TB3 terminals 1 and 2 are connected, and
TB2 terminals 4 and 5 are connected.
In the energize-to-trip version, if input power to the ProTech 203
system is lost, the interposing relay will not actuate, and TB3
terminals 2 and 3 and TB2 terminals 5 and 6 will remain connected.
The ProTech 203 system utilizes three separate speed-sensing units that are
interfaced to three individual magnetic pickups (MPUs). Each speed sensing unit
(A, B, and C) actuates two voter relays that are internally wired in a six relay
series/parallel configuration. This six-relay configuration drives the interposing
relay shown in Figure 3-3.
Whenever two of the three speed-sensing circuits sense an overspeed condition,
the voter relay configuration will change state, causing a turbine trip. It should be
noted, however, that a single MPU or circuit failure will not cause an inadvertent
trip.