Control Differential Transmitter
It can be used to produce a rotation equal to the sum of difference of the rotations of two shafts. The arrangement for this purpose is shown in Fig. 39.20 (a). Here, a CDX is coupled to a control transmitter on one side and a control receiver on the other. The CX and CR rotor windings are energized from the same single-phase voltage supply.
It has two inputs : Mechanical q and Electrical f and the output is Machnical (q – f). The mechanical input (q) to CX is converted and applied to the CDX stator. With a rotor input (f), the electrical output of the CDX is applied to the CR stator which provides the mechanical output (q – f).
As shown in Fig. 39.20 (b), if any two stator connections between CX and CDX are transposed, the electrical input from CX to CDX becomes -q, hence the output becomes (-q – f) = – (q + f).
Control Differential Receiver
In construction, it is similar to a CDX but it accepts two electrical input angles and provide the difference angle as a mechanical output (Fig. 39.21).
The arrangement consists of two control transmitters coupled to a CDR. The two control transmitters provide inputs to the CDX, one (q) to the stator and the other (f) to the rotor. The CDX output is the difference of the two inputs i.e.
