MIL-PRF-17773 Switches, Bus Transfer, Electric Power Automatic And ManualThis specification covers the Automatic Bus Transfer Switch \(ABT\) \(see 6.4.1\) and the Manual Bus Transfer Switch \(MBT\) \(see 6.4.13\), herein referred to as ABT, MBT, or switch\(es\), for use on surface and submarine Naval vessels. Unless otherwise specified herein, this specification applies to both ABTs and MBTs. Requirements for Static or Solid State ABTs \(SABTs\) are not defined in this specification. MIL-PRF-32150 specifies requirements for SABTs.

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MIL-PRF-17773C(SH)

3.4.15 Electrostatic discharge (ESD) protection requirements. The use of electrostatic discharge (ESD)

sensitive components is discouraged. When specific parts, modules, connectors/receptacles or subassemblies

sensitive to damage by ESD are used, the devices shall be clearly marked with ESD labeling in accordance with

MIL-STD-1686. The symbol shall be located in a position readily visible to personnel when that assembly is

incorporated into its next higher assembly.

3.4.16 Ungrounded circuits. Switches shall operate in ungrounded systems.

3.4.17 Continuous duty. Switches shall operate at continuous duty (100 percent) (see 6.4.4).

3.4.18 Electromagnetic interference (EMI). When specified (see 6.2), enclosures shall comply with MIL-STD-

461.

3.4.19 Conducted emissions. The ABT shall not exceed the CE101 and CE102 limits of MIL-STD-461.

Additionally, the upper limit of CE101 shall be extended to 20 KHz.

3.4.20 Conducted susceptibility. The ABT shall meet the specified performance requirements per the CS101,

CS114, and CS116 limits of MIL-STD-461.

3.4.21 Conducted susceptibility spikes, power leads. The ABT shall not exhibit any malfunction, degradation

of performance, or deviation from specified indications when tested in accordance with 4.6.6.

3.4.22 Radiated emissions, AC magnetic field. The ABT shall not exceed the RE101 limits of MIL-STD-461.

3.4.23 Radiated emissions, AC electric field. The ABT shall not exceed the RE102 limits of MIL-STD-461.

3.4.24 Radiated susceptibility, AC magnetic field. The ABT shall meet the specified performance requirements

in an AC magnetic field in accordance with the RS101 limits of MIL-STD-461.

3.4.25 Radiated susceptibility, DC magnetic field. The ABT shall be compatible with the magnetic field

environment interface constraints of DOD-STD-1399-070-1.

3.4.26 Radiated susceptibility, AC electric field. The ABT shall meet the specified performance requirements

in an electric field per the RS103 limits of MIL-STD-461.

3.4.27 Radiated susceptibility, magnetic and electric fields, spikes and power frequencies. The ABT shall not

exhibit any malfunction, degradation of performance or deviation from specified indications when tested in

accordance with MIL-STD-461 and 4.6.11.

3.4.28 Power. Switches shall operate in accordance with MIL-STD-1399-300 and shall not introduce negative

electrical characteristics to exceed the values specified therein during steady-state operation and during transfer.

The ABT shall not introduce transients or noise in excess of that defined and allowed by MIL-STD-1399-300.

3.4.29 Safety. Switches shall operate in a safe manner such that two procedural errors, or the malfunction of

any single hardware or software component or element, shall not result in catastrophic hazards, causing death,

system loss, or severe environmental damage, or critical hazards, causing severe injury, severe occupational illness,

or major system or environmental damage. Safety requirements for the equipment shall be in accordance with MIL-

E-917. A safety ground shall be provided on all equipment in accordance with UL 60950.

3.4.30 Personnel electrical safety.

3.4.30.1 High voltage protection. Protection from dangerous voltages (30 to 500 Vrms or 30 to 500 VDC) shall

be provided by the use of guards, grounding, and warning placards in accordance with MIL-E-917. Assemblies

operating at potentials exceeding 500 Vrms or 500 VDC shall be completely enclosed. The maximum discharge

time shall be ten seconds to discharge components or assemblies from their operating voltages to 30 Vrms or less.

3.4.30.2 High current protection. Protection from shock hazards that can occur from contact with current

producing circuitry of 21 mA AC or 80 mA DC at a potential of greater than 30 VDC or 30 Vrms shall be provided.

For high current (greater than or equal to 25 amps) power sources, positive design measure shall be incorporated by

the use of guards, barriers, and warning placards.