12.02.2014 Views

Radar System Engineering

Radar System Engineering

Radar System Engineering

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

578 PRIME POWER SUPPLIES FOR RADAR [SEC. 14.6<br />

that would generate a frequency above resonance, the machine speed<br />

would continue to increase, being limited only by friction and windage<br />

losses.<br />

CentrifWal Control.—The most recent method of speed regulation<br />

to be used on aircraft inverters is a carbon-pile governor as used by<br />

the Holtzer-Cabot Electric Company. It is shown in Fig. 14.20 and also<br />

in Fig. 14.21 mounted on a 750-va PU-16 inverter. The electrical<br />

connections are shown in the schematic diagram Fig. 14.22. A centrifugal<br />

device on the end of the inverter shaft acts against the carbon pile<br />

in such a manner that increased speed will reduce the m-essure on the<br />

carbon pile and reduced speed will increase the pressure. As shown in<br />

Fig. 14.20, when the machine is at rest the carbon pile is held in compres-<br />

Alternator fwld<br />

h<br />

filter Contactor<br />

.. A L~~~ .Itemator Cabwle I<br />

;,S1l,<br />

~ ,;gt<br />

FIG. 14.22.4chematic<br />

T<br />

A-c<br />

Ofi 1<br />

fifter =<br />

%ries<br />

fwld<br />

Voltage<br />

adwstmg<br />

“’’’t”’<br />

-f-l&q .<br />

diagram of Wincharger PU-16 aircraft inverter, 750va, 115volts,<br />

400Cps.<br />

sion by the large coil spring in the rotating element. The resistance<br />

is then least, giving maximum field for good starting characteristics. As<br />

the machine speed increases, the centrifugal weights compress the spring<br />

and reduce the pressure on the pile, increasing its resistance. Should<br />

the machine exceed its rated speed, the carbon pile will be compressed by<br />

the spring under the adjusting screw. At rated speed, the carbon pile<br />

is balanced between these two springs and a slight change in speed will<br />

cause a relatively large change in resistance. Springs A and B position<br />

the tube holding the carbon pile. I<br />

Electronic Speed Controls.—The Eclipse-Pioneer Division of Bendix<br />

Aviation has recently developed an electronic speed control for use on<br />

motor alternator sets of 1500-va capacity and larger. This regulator is<br />

designed to hold speed within the limits of Army-Navy Specification<br />

AN-I-lo.<br />

1C. T. Button, “.4 Carbon-pile Speed Governor, ” A lEE Transactions, 65, 4<br />

(January 1946).

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!