Woodward 8923-2146 Turbine Shutdown Trip Block Assemblies

MicroNet controls require a fixed wiring installation for ac applications. Ground leakage exceeds 3.5 mA

AC. Maximum ground leakage for ac installations is 7.2 mA at 60 Hz. A ground conductor connected to

the chassis is required for safety. The power supply grounding terminal(s) should also be connected to

earth to ensure grounding of the power supply printed circuit boards. The grounding conductor must be

the same size as the main supply conductors.

Branch circuit fuses, circuit breakers, and wiring must meet appropriate codes and authorities having

jurisdiction for the specific country (CE, UL, etc.). See Table 4-4 for maximum recommended fuse or

breaker ratings. Do not connect more than one main power supply to any one fuse or circuit breaker. Use

only the wire sizes specified in Table 4-4 which meet local code requirements. Time delay fuses or circuit

breakers must be used to prevent nuisance trips.

Power requirements depend on the number and type of modules supplied for each system. For a system

with a single I/O chassis, size the input power source according to the rating of the MicroNet power

supply to which the source is connected. Do not size the supply mains for the sum of the MicroNet power

supply ratings when redundant supplies are used. MicroNet supplies are redundant when installed in the

same chassis. Redundant supplies share the load between them equally, but each must provide for full

load in the event that one of the units is disabled. Table 4-4 gives the maximum overload protection for

supply mains connected to any single or redundant pair of MicroNet main power supplies. It is not

recommended that both MicroNet main power supplies of a redundant pair be connected to a single

source, since failure of that source would disable the system.