Figure 1-42.-No-break "uninterrupted" power supply system, block diagram.

OPERATION

The control cabinet contains all the control and

monitoring equipments. The motor generator is a single-

Normal ship's power (fig. 1-42) is applied to the

shaft unit. Either section of the motor generator can

voltage and frequency monitors. If the monitors sense

perform as the motor with the other as the generator.

the normal power to be within the frequency and voltage

This permits two operational modes: NORMAL and

limits required relay action (relay #1) will allow the

STOP GAP.

normal power to be applied to the load and other cir-

NORMAL operation uses the normal supply (ship's

cuitry. (It should be noted that the relay numbers in

generators). The motor generator is driven by the ac

fig. 1-41 refer to relay action sequence rather than relay

motor from the ship's supply, and the dc generator

designations.) Power is applied to the relay control

charges the batteries.

power circuit from the battery.

In STOP GAP operation, the motor generator is

When the system is turned on, the motor generator

driven by the dc motor with power from the batteries.

will accelerate to approximately synchronous speed

Under this condition the ac generator provides power to

as an induction motor before a time delay relay is

the critical load.

Figure 1-42.-No-break "uninterrupted" power supply system, block diagram.

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