# 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.