The most revered section was always the troubleshooting guide. “Synchro system hunting?” the handbook would ask. “Check velocity damping. Increase tachometer gain or add a lead network.” “Null voltage too high?” “Verify orthogonality of stator windings.” It was diagnostic jazz, not simple checklists.
This is the story of that handbook, the technology it champions, and why, in an age of digital abundance, its principles remain utterly indispensable. To understand the handbook, one must first understand the components at its heart. A synchro is, in essence, a rotary transformer. It looks like a small, precision motor but behaves like an analog computer. When you rotate its rotor, it outputs a set of three voltages (or receives them) that encode the exact angular position of a shaft. No glass disks, no LEDs, no fragile optics—just copper windings and a magnetic field. Synchro And Resolver Engineering Handbook Moog Inc
Because in motion control, as in life, the angle is everything. And nobody ever explained the angle better than Moog. This feature is a tribute to the technical writers, applications engineers, and analog designers at Moog Inc. who created and maintained the Synchro and Resolver Engineering Handbook—a work that continues to turn up on desks from Cape Canaveral to Shenzhen. The most revered section was always the troubleshooting
In the pantheon of great technical reference manuals—texts like Radar Handbook (Skolnik) or The Art of Electronics (Horowitz & Hill)—there exists a quieter, more specialized volume. Its spine is often cracked, its pages smudged with the fingerprints of three generations of engineers. It is the Synchro and Resolver Engineering Handbook from Moog Inc. Increase tachometer gain or add a lead network
But a servovalve is useless without a command. And that command, in early fly-by-wire systems, missile guidance platforms, and naval gun directors, came from synchros and resolvers.
Moog’s handbook didn’t just explain what they were; it explained how to weaponize them . It provided the transfer functions, the Scott-T transformer connections to convert three-wire synchro data to two-wire resolver data, and the critical error budgets that separate a functioning radar dish from a gimbal lock in an inertial navigation system. The handbook emerged from a specific historical cauldron: the Cold War aerospace boom of the 1960s. Moog, founded by William C. Moog (whose brother, “Bill” Moog, invented the Moog synthesizer—a neat footnote of analog genius running in the family), was already the leader in high-performance servovalves.
In a conference room in East Aurora, New York (Moog’s global headquarters), there is probably a worn copy on a shelf. And somewhere right now, an engineer is opening a PDF of that same handbook. They are trying to figure out why their resolver’s sine-cosine mismatch is 0.5% at 25°C but 1.2% at 85°C. They will find the answer in a footnote on page 4-17. And they will be grateful.