The CP series SCR power controllers are multi-zone power controllers that can be configured for phase angle fired, zero voltage switched or on-off solid state contactor control of directly connected electric heaters. The CP will not control transformers or motors. This is accomplished by phase angle firing, or variable time based zero voltage switching a pair of inversely connected SCR's. Up to eight zones available on a single chassis. Single phase and three phase options.
Unit of Measure


Voltage Designations

N/A 240 VAC 50/60 Hz



Output Voltage

N/A 0 to 97% of Input Voltage Phase Angle

Control Signal (CP Phase Angle)

N/A 4 to 20 mA at 1.5 volts DC per zone

Input Impedance

N/A 75 ohms per zone


N/A Less than 15% deviation

Response Time

N/A 12 mS (STD unit, non soft start)


N/A 190 ºF (fan cooled units only)

Power Dissipation (Watts)

N/A 1.2 x maximum current

Zone Designations

N/A 3

Method of Firing

N/A P-Phase Angle Fired

Ordering Note

N/A 150-1200 Amp units only available in 2 or 3 legs.

Phase Angle Options

Soft Start

N/A S-3 Seconds S02-2 Seconds

Current Limit

N/A CL- Current Limit CLP-Current Limit with Panel Mount Potentiometer

Voltage Limit

N/A VL-Standard 1 Turn PCB VL25-25 Turn PCB

3-Phase Control Options

N/A 3-leg phase angle fired, A3P style, add “3P” to part number.
Example: 6CP-48-70-3P has six SCR-diode packs, controlling two 3-phase heater loads.

For 4-wire 3-phase angle fired, use standard single phase controlled leg, wiring the three control circuit cards 4-20 mA command signal in series.


N/A All Avatar Instruments products carry a full five year, warranty from date of purchase, parts and labor warranty against component failure and defects in workmanship . In the event your controller fails to perform properly, contact Avatar to obtain a return authorization number. Controllers sent to Avatar for warranty service that have no apparent defect will be treated as a standard repair and a $50.00 charge will be applied. Avatar will repair or replace any unit that failed due to defective parts or assembly. This warranty DOES NOT cover damage due to shipping, abuse, misapplication or operation beyond specified rating. Further more fuses and improperly fused SCR's are NOT COVERED by this warranty. Avatar is not responsible for any subsequent or other damage experienced in use of this device.



  • UL 508 listed
  • Compact and light weight
  • 100 % solid state circuitry
  • Over-rated SCR power modules
  • Over-sized heat sink
  • Full power ratings up to 50 ºC (122 ºF) ambient temperature
  • Optically isolated 4-20 mA input standard
  • Versatile “building block” custom configurations
  • Electrically isolated chassis and heat sinks to 600 Amps
  • Gold alodined chassis and heat sink
  • MOV protection on all power SCR's
  • SanRex, SemiKron, International Rectifier and Fairchild semiconductors
  • Double sided FR4 VO-94 rated glass epoxy PCB's
  • Theory of Operation


    These controls proportionally turn on a percentage of each power line half cycle. This gives smooth, infinitely variable application of power to the heaters. Imagine a light dimmer and how it provides power to
    The standard input signal (4-20 mA) is applied to the blue input terminal block, processed and fed to an optical coupler. The output of the optocoupler feeds the drive circuitry which is then fed to a pair of inversely connected SCR's. Additionally, an MOV (metal oxide varistor) is connected in parallel with the SCR's, providing voltage spike protection to the controller.