## 3-Phase Voltage Sources

The simple phase tripler circuit on the right can be used to do a variety of 3-phase experiments. It has the same capability as the BD-3A60k 60Hz Phase Tripler kit. All resistors should be 0.25W, 1% tolerance. C1 and C2 should be 2% or 5% tolerance.

The input should be a 60Hz sinewave with an amplitude between 0 and 18Vpp. The output amplitude for each phase will be the same as the input amplitude.

The following changes will make the circuit a 400Hz phase tripler:
C1, C2 = 39nF, 2%.    R4 = 18.8K, 1%.    R7 = 5.9K, 1%.

Output voltage:  0 to 18V p-p, each phase output, P0, P1, P2 to common, G.
Output power:  125mW maximum, each phase output, P1, P2, P3.
Output frequency: 60Hz or 400Hz, ±1%.   P0 = 0 deg.  P2 = 120 deg.  P3 = 240 deg.
Input: 0 to 18V p-p, 60Hz or 400Hz, ±1%.
Input power: +12VDC and -12VDC, 100mA maximum.

## Electronic Control Systems: PID-X1

PID-X1 Circuit

Versatile, multimode, PID feedback controller. PID parameters can be varied with external resistors and capacitors on the breadboard. Use it as a P, PI, or PID controller.

It can be used for most of the feedback control experiments in the Electronic Control Systems book. Or design your own circuits and experiments.

Gains are given by:

With the parts included in the kit the practical range of the gains are:

Kp: 1 to 100
Ki: 4/second to 1000/second
Kd: 22milli-seconds to 22seconds

(R5 = 100k, R7 = 2.2Meg, C2 = 1uF)

U1A is a unity gain differential amplifier. Its output is the error voltage VE, which is the difference between the set point voltage, VSP, and the process variable voltage, VPV.

U1B is a proportional amplifier whose gain is controlled by Rp.

U2A is an integrator whose gain is controlled by Ri.

U2B is a differentiator whose gain is controlled by Cd

U3A is a unity gain summer that sums the PID output voltages and the offset voltage. R15 controls the offset (equilibrium) voltage.

The U3B circuit may be used to simulate a process with a time constant of tc = R12·C4 = 0.1 second.