SYNCHRO ZEROING METHODS are various and depend upon the facilities and tools available,
and how the synchros are connected in the system. Some of the more common zeroing methods are the
voltmeter, the electric-lock, and the synchro-tester methods.
The VOLTMETER ZEROING METHOD is the most accurate and requires a precision voltmeter.
This method has two major steps-the coarse or approximate setting and the fine setting. The coarse setting
ensures the synchro is not zeroed 180º away from its reference. This setting may be approximated
physically by aligning two marks on the synchro. The fine setting is where the synchro is precisely set on
ELECTRICAL-LOCK ZEROING METHOD is perhaps the fastest. However, this method can be
used only if the rotors of the synchros are free to turn and the leads are accessible. For this reason, this
method is usually used on TRs.