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870 Series SCR Control Panel

The 870 Series SCR Control panel is a fully proportional process temperature control panel that utilizes SCR Power Controllers to modulate the entire heater load directly, varying the heater output from 0 to 100% of the total heater KW. Working on a four second time base, the heater will be energized only for the number of AC cycles necessary to produce the exact amount of heat required. The resulting precise control and rapid response make the 870 Series SCR Control Panel the best choice for applications that must accommodate material flow changes and still provide precise temperature control. The panel is completely assembled, pre-wired, tested, and ready for troublefree installation and operation. Designed for use in industrial environments and outdoor installations.

  • UL Listed/CSA Approved
  • NEMA 4/12 painted steel enclosure1
  • PID self-tuning temperature controller (adjustable process temperature with standard type “J” thermo-couple input)
  • Over-temperature controller (adjustable temperature limit with standard type “K” thermocouple input)
  • Disconnecting 50 amp safety contactor for resistive loads (per circuit)
  • 120 VAC control power transformer with primary and secondary fusing
  • Power circuit fusing
  • Three-phase, zero cross-fired SCR power controllers
  • Door interlocking disconnect switch
  • Manual reset pushbutton with built-in pilot light (red) for “OVER-TEMPERATURE” alarm
  • Selector Switch – ON/OFF with built-in pilot light (green) for “POWER ON” indication
  • Terminals for customer supplied remote interlock
  • Wiring diagram permanently affixed to the inside of the cover
  • Short Circuit Current Rating of 5KA

Optional Features

Control Relays

These relays are activated by safety devices, such as a flow switch or remote shutoff.

Indicator Lights

Additional indicator lights may be specified for visual indication of system status, such as "LOW TEMPERATURE".

Audible Alarm Package

Includes a horn, pilot light, latching relay and a push button for silencing the horn.

Low Liquid Cutoff

The relay is mounted and wired with sensing probe shipped loose for field installation.

Motor Starter

This package consists of a motor starter for pump motor start-up. Motor starter is internally mounted and field connected to the pump motor.

Special Controllers

The customer may specify the use of special process or over-temperature controllers for a different temperature range, sensor input, control mode, etc.

Panel Heater

A heater and thermostat are provided to prevent condensation and maintain minimum ambient temperature for electrical components.

Wire Markers

Identification markers are attached to both ends of all control and power wires.

Tagging of Internal Parts

Permanent tags are attached to the subpanel near internal parts and marked with component titles as noted on the wiring diagram.

Explosion-Resistant Panel

A cast aluminum enclosure is rated for Class I, Groups C & D and Class II, Groups E, F & G (NEMA 7, 9).

Purged Panels

Type Z for Class I, Division 2 areas Type X for Class I, Division 1 areas.

Optional Temperature Inputs

Type "K" thermocouple inputs or "RTD" inputs.

Stainless Steel Panel Enclosure (NEMA 4X)

This con-struction provides extra corrosion resistance for harsh environments1.

Special Ratings

65 KA interupting amp rating.

(1) Agency listed for NEMA 4 only.


For product specifications, refer to our technical document center.