Three Phase AC
Three Phase, Zero Cross:
The term Zero-Cross (synchronous operation of SCR's) is derived from the fact that the SCR's are turned on only when the instantaneous value of the sinusoidal wave is zero. In Zero-Cross operation, power is applied for a number of continuous half-cycles and then removed for a number of half-cycles to achieve the desired load power in the same manner as power would be controlled with a mechanical switching device. The frequency of the on-off cycles can be extremely fast because there is no limit to the number of switching operations the SCR can perform.
3 Phase, Phase Angle:
In phase-angle control, each SCR of the back-to-back pair is turned on for a variable portion of the half-cycle that it conducts. Power is regulated by advancing or delaying the point at which the SCR is turned on within each half cycle. Light dimmers are an example of Phase-Angle control.
| Model | Phases | Firing Mode | Output | Current Low | Current High | Highlights |
|---|---|---|---|---|---|---|
| MicroFUSION Three Phase | Three phase | Phase angle, Zero cross, Zero Cross Transformer Mode, Fast Zero Cross | AC | 8 | 400 |
MicroFUSION is an ultra-compact high performance digital SCR controller that adapts to the analog environment as well as the digital environment. |
| FUSION Three Phase (AC) Power Controller 500 - 1200A | Three phase | Phase angle, Zero cross, Fast Zero Cross | AC | 500 | 1 200 |
24 - 600 Vac. A microprocessor-based SCR controller operating both analog and digital interfaces. A phase angle or zero cross fired SCR controller which linearly controls, with respect to the setpoint, the AC voltage, current, or true power applied to a three phase electrical load. The 3 phase controller can be ordered in either 2 or 3 leg control with 2 leg being limited to zero cross firing. Control is achieved for 3 leg by three pairs of inverse parallel SCRs or in 2 leg by 2 pairs of inverse parallel SCRs. |