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Radar System Engineering

Radar System Engineering

Radar System Engineering

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568 PRIME POWER SUPPLIES FOR RADAR [SEC. 14.5<br />

the a-c voltage, which in a radar set shows up as spoking and blurring of<br />

the indicator scope (see Fig. 14.11). The frequency of the modulation<br />

is normally 30 or 40 cps. The maximum “jitter” which can be tolerated<br />

is approximately 1 to 1+ volts.<br />

The regulator should be shock-mounted as shown in Fig. 14.12.<br />

This procedure, together with adjustment of the regulator on the tight<br />

side of the dip, helps not only in clearing up the troubles mentioned above,<br />

but also in increasing the interval between regulator adjustments, and<br />

in reducing the wear of the carbon disks.<br />

The carbon-pile regulator is affected by moisture. Moisture in the<br />

carbon pile materially reduces the resistance, and frequently when a<br />

motor-alternator is started after having stood for some time in an atmosphere<br />

saturated with water vapor the output voltage is high—approximately<br />

135 to 145 volts. After the machine has run for an hour or<br />

longer, the moisture is usually driven off and the voltage returns to<br />

normal. During this drying-out period the carbon disks are often

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