1-52 Q-62. When is a synchro receiver (TR) properly zeroed? Q-63. What should a voltmeter read when a TX is set on coarse zero? Q-64. What precaution should you take when you use 115 volts to zero a differential? Q-65. Why should a synchro be rechecked for zero after it is clamped down? Q-66. What is the output voltage of a CT when it is set on electrical zero? Q-67. When you zero a multispeed synchro system which synchro should you zero first? ELECTRICAL LOCK METHOD The electrical lock method, although not as accurate as the voltmeter method, is perhaps tile fastest method of zeroing synchros. However, this method can be used only if the rotors of the units to be zeroed are free to turn and the lead connections are accessible. For this reason, this method is usually used on the TR because, unlike transmitters, the TR shaft is free to turn. To zero a synchro by the electrical lock method, deenergize the unit, connect the leads as shown in figure 1-41, and apply power. The synchro rotor will then quickly snap to the electrical zero position and lock. If the indicating device connected to the synchro shaft does not point to zero, loosen the synchro in its mounting and rotate it until the zero position of the indicator corresponds with the electrical zero of the synchro. As we stated previously, youmayuse115voltsasthepowersourceinsteadof78volts,providedyoudonotleavetheunitconnectedformorethan2minutes.Figure 1-41.—Zeroing a synchro by the electrical lock method. SYNCHRO TESTERS Two types of synchro testers are shown in figure 1-42, view (A) and view (B). Each is nothing more than a synchro receiver on which a calibrated dial is mounted.
Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business
