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.

Phase-angle control provides a very fine resolution of power and is used to control fast responding loads such as tungsten-filament lamps or loads in which the resistance changes as a function of temperature. Phase-angle control is required if the load is transformer-coupled or inductive.

Phase-angle controllers are typically more expensive than zero-cross controllers because the phase-angle circuit requires more sophistication than does a zero-cross circuit. Phase-angle control of three-phase power requires SCR's in all three legs and is appreciably more expensive than zero-cross control which only requires SCR's in two of the three legs.

Model Phases Firing Mode Output Current Low Current High Highlights
Multizone MicroFUSION Single phase Phase angle, Zero cross, Zero Cross Transformer Mode AC 8 400

MicroFUSION is an ultra-compact high-performance microprocessor-based power controller, available in single or three phase models to control AC loads. 

MicroFUSION Three Phase Three phase Phase angle, Zero cross, Zero Cross Transformer Mode 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.

MicroFUSION Single Phase Single phase Phase angle, Zero cross, Zero Cross Transformer Mode 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 (DC) Power Controller Three phase Phase angle DC 60 1 400

24 - 600 Vac. A microprocessor-based DC SCR controller operating both analog and digital interfaces. A phase angle-fired controller which linearly controls, with respect to the setpoint, the DC voltage, current, or true power applied to an electrical load. Control is achieved by means of a six SCR bridge with freewheeling diode.

FUSION Three Phase (AC) Power Controller Three phase Phase angle, Zero cross, Burst AC 50 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.

FUSION Single Phase (DC) Power Controller Single phase Phase angle DC 45 1 080

24 - 600 Vac. A microprocessor-based DC SCR controller operating both analog and digital interfaces. A phase angle fired controller which linearly controls, with respect to the setpoint, the DC voltage, current, or true power applied to an electrical load. Control is achieved by means of a half controlled SCR bridge.

FUSION Single Phase (AC) Power Controller Single phase Phase angle, Zero cross, Burst AC 50 1 200

24 - 600 Vac. A microprocessor-based SCR controller operating both analog and digital interfaces. A phase angle or zero cross fired controller which linearly controls, with respect to the setpoint, the AC voltage, current, or true power applied to an electrical load. Control is achieved by means of a pair of inverse parallel SCRs.

Compact FUSION Three Phase Power Controller Three phase Phase angle, Zero cross, Burst AC 10 160

24 - 600 Vac. A microprocessor-based SCR controller operating both analog and digital interfaces. Can be ordered in either 2 or 3 leg control with 2 leg being limited to zero cross firing. Output is controlled linearly with respect to command signal and can be set to the average or RMS value of the voltage or current, as well as true instantaneous power or external feedback.

Compact FUSION - Single Phase Power Controller Single phase Phase angle, Zero cross, Burst AC 10 160

24 - 600 Vac. A microprocessor-based SCR controller, operating with both analog and digital interfaces. Output is controlled linearly with respect to command signal and can be set to the average or RMS value of the voltage or current, as well as true instantaneous power or external feedback.

3869 Three Phase DC Power Controller Three phase Phase angle DC 300 400

120 - 480 Vac. DC SCR Controller. Accepts most commands. High current, three phase DC output.

3629C Three Phase Power Controller Three phase Phase angle AC 50 1 000

208 - 575 Vac. Three Phase SCR Controller. Higher current ratings than our solid state relay models. Features include: current limiting, over-current trip, shorted SCR detection.

2022 AC Single Phase Power Controller Single phase Phase angle AC 10 70

120 - 575 Vac. Analog SCR Controller. Accepts most commands. Dual setpoints for fast transitions.

1825 DC Power Controller Single phase Phase angle DC 10 30

120 - 240 Vac. Analog SCR Controller. Accepts mA commands. 120Hz fullwave DC output.

1822 DC Power Controller Single phase Phase angle DC 10 30

120 - 240 Vac. Analog SCR Controller. Accepts Vdc or potentiometer commands. 120Hz fullwave DC output.

1802 / 1805 DC Power Controller Single phase Phase angle DC 10 40

120 - 570 Vac. Analog SCR Controller. Accepts Vdc or potentiometer commands. 60Hz halfwave DC output.

1600 (Multi-zone) Power Controller Single phase Phase angle, Zero cross AC 10 70

120 to 575 Vac. Multi-zone SCR Controller. Accepts most commands. Allows mixing of line voltages and load currents for multiple zones in a small footprint.

1032A Single phase Phase angle AC 10 70

120 - 575 Vac. SCR controller that accepts most commands. Field adjustable current limiting.

1029D Single phase Phase angle AC 50 2 000

120 to 575 Vac. Analog SCR Controller. Higher current ratings than our solid state relay models. Features include: current limiting, shorted SCR detection, over-current trip, metering outputs, user selectable feedback modes.

1025 Single phase Phase angle AC 10 70

120 - 480 Vac. Analog SCR Controllers. Accepts mA commands.

1022 Single phase Phase angle AC 10 70

120 - 480 Vac. Analog SCR Controllers. Accepts Vdc and potentiometer commands.