Synchro — And Resolver Engineering Handbook Moog Inc

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.

Moreover, the handbook teaches a mindset. It teaches that a position sensor is not a black box that spits out bits. It is an impedance network, a transformer with a rotating coupling coefficient, a source of quadrature error and harmonic distortion. To truly debug a motion system, you must think like the handbook: with a vector network analyzer in one hand and a deep respect for analog imperfections in the other. If you are lucky enough to find an original printed copy from the 1980s—spiral-bound, with a faded blue cover and the old Moog “M” logo—you possess a piece of engineering history. Flip to any random page. You will see hand-drawn figures, typewritten equations (with corrections in pen from some long-ago applications engineer), and a purity of purpose that modern documentation rarely achieves. Synchro And Resolver Engineering Handbook Moog Inc

The answer lies in edge cases. When a resolver cable runs 50 meters through a factory with VFDs spewing common-mode noise, the handbook’s sections on “Shield Termination” and “Twisted-Pair Routing” become priceless. When a resolver’s output voltage sags because the excitation frequency drifted due to a cheap oscillator, the handbook’s graphs of “Output vs. Frequency” show you exactly how much error to expect. When you need to build a redundancy management system—three resolvers on one shaft, voting on position—the handbook’s discussion of “dual-speed resolvers” and “electrical zero alignment” is the only guide you’ll find. This is the story of that handbook, the

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. It looks like a small, precision motor but

Many companies stopped printing their handbooks. But Moog, stubbornly analog, kept the Synchro and Resolver Engineering Handbook in print—or at least available as a PDF. Why? Because the real world is analog.