Constant Resistance

Nickel Chronium, Iron Chronium

Controllers recommended for constant resistance loads are listed below:

Model	Phase	Mode	Voltage	Current	Highlights
1020	One	Zero Cross	120-575 Vac	10-70 Amps	Powered off of the 4/20mA loop, so no control transformer is required.
1021A	One	Zero Cross	120-575 Vac	10-70 Amps	Accepts most commands.
1021B	One	Zero Cross	120-575 Vac	10-70 Amps	Accepts most commands. Sync-guard smoothes out line current draw when multiple controllers are in use.
1022	One	Phase Angle	120-575 Vac	10-70 Amps	Accepts Vdc and potentiometer commands.
1025	One	Phase Angle	120-575 Vac	10-70 Amps	Accepts mA commands.
1027A	One	Zero Cross	120-575 Vac	50-160 Amps	Accepts most commands. Features include: Sync-guard and Trans-guard.
1029D	One	Phase Angle	120-575 Vac	50-2000 Amps	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.
1032A	One	Phase Angle	120-575 Vac	10-70 Amps	Accepts most commands. Field adjustable current limiting.
1600	One/Three	Phase Angle or Zero Cross	120-575 Vac	10-70 Amps	Accepts most commands. Allows mixing of line voltages and load currents for multiple zones in a small footprint.
2022	One	Phase Angle	120-575 Vac	10-70 Amps	Accepts most commands. Dual setpoints for fast transistions.
3020	Three	Zero Cross	120-575 Vac	10-70 Amps	Powered off of the 4/20mA loop, so no control transformer is required.
3021A	Three	Zero Cross	120-575 Vac	10-70 Amps	Accepts most commands.
3021B	Three	Zero Cross	120-575 Vac	10-70 Amps	Accepts most commands. Sync-guard smoothes out line current draw when multiple controllers are in use.
3027	Three	Zero Cross	120-575 Vac	85-750 Amps	Accepts most commands. Features include: Sync-guard, Trans-guard and on-board line fusing for most frame sizes.
3037	Three	Zero Cross	120-575 Vac	85-750 Amps	Accepts most commands. Features include: Sync-guard, Trans-guard, Shorted SCR detection and on-board line fusing for most frame sizes.
3321A	Three	Zero Cross	120-575 Vac	10-70 Amps	Accepts most commands.
3337	Three	Zero Cross	208-575 Vac	200-750 Amps	Accepts most commands. Features include: Sync-guard, Trans-guard, Shorted SCR detection and on-board line fusing for most frame sizes.
3629C	Three	Phase Angle	208-575 Vac	50-1000 Amps	Higher current ratings than our solid state relay models. Features include: current limiting, shorted SCR detection, over-current trip.
FUSION Single Phase AC	One	Phase Angle or Zero Cross, Zero Cross Transformer Mode	24-600 Vac, 45-65 Hz (Auto-Ranging)	50 - 1200 Amps	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.
FUSION Single Phase DC	One	Phase Angle or Zero Cross, Zero Cross Transformer Mode	24-600 Vac, 45-65 Hz (Auto-Ranging)	45 - 1080 Amps	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 Three Phase AC	Three	Phase Angle or Zero Cross, Zero Cross Transformer Mode	24 - 600 Vac, 45 - 65 Hz (Auto-Ranging)	50 - 1200 Amps	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 Three Phase DC	Three	Phase Angle or Zero Cross, Zero Cross Transformer Mode	24 - 600 Vac, 45 - 65 Hz (Auto-Ranging)	60 - 1400 Amps Full Wave Rectified	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.
Compact FUSION Single Phase	One	Phase Angle, Zero Cross, Burst, Zero Cross Transformer Mode	24-600 Vac, 45-65 Hz (Auto-Ranging)	10 - 160 Amps	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.
Compact FUSION Three Phase	Three	Phase Angle, Zero Cross, Burst, Zero Cross Transformer Mode	24-600 Vac, 45-65 Hz (Auto-Ranging)	10 - 160 Amps	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.
MicroFUSION Single Phase	One	Phase angle, Zero cross, Zero Cross Transformer Mode	24-600 Vac, 45-65 Hz (Auto-Ranging)	8 - 400 Amps	MicroFUSION is an ultra-compact high performance digital SCR controller that adapts to the analog environment as well as the digital environment.
MicroFUSION Three Phase	Three	Phase angle, Zero cross, Zero Cross Transformer Mode	24-600 Vac, 45-65 Hz (Auto-Ranging)	8 - 400 Amps	MicroFUSION is an ultra-compact high performance digital SCR controller that adapts to the analog environment as well as the digital environment.

Learn more about firing modes here.

Learn more about load connections here.