In reality, the resolver sensor is basically a
rotary transformer. Because its reliability comes from its simplicity, it can withstand the same environmental hazards as the motor it tracks.
The electrical connection is made to the stationary coil, but a
rotary transformer is required for temperature sensing.
An induction coil in the rotor and an adjacent coil in the stator work together as a radio frequency
rotary transformer. This transformer has two functions.
A resolver is a
rotary transformer that puts out a variable voltage signal and is typically more expensive than an encoder.
The power is sent to the balancer by means of a
rotary transformer developed and patented by BalaDyne.
On the basis of methods for power and signal transfer between stationary and rotating environments in torque measurement; rotary torque sensors have been further segmented into slip-rings,
rotary transformers, rotary electronics, FM telemetry and so on.
For decades, slip ring and
rotary transformers have been used to measure torque.