BASIC ECD CONTROL
     The standard ECD control is a compact printed circuit design utilizing integrated circuits and an encapsulated SCR cube. Component designations are printed on the circuit boards for easy identification.      The basic controller provides speed regulation of 1% of maximum speed throughout the published speed range. Regulation is maintained for loads from 25 to 100% of full load. Linear acceleration control is supplied as standard to provide smooth, uniform starting, adjustable from 2 to 20 seconds. Maximum and minimum speed and gain adjustments are also provided as standard

HOW IT WORKS
     The ECD control has a regulated reference voltage which is adjustable by the speed selection control in; the operator's station. The AC tachometer on the output shaft of the drive produces a voltage proportional to speed. The control compares the desired speed from the speed selection control with the actual speed from the tachometer and changes the coil excitation in the direction required to correct and hold the drive at the desired speed.
     ` The ECD is operated by controlling only low power coil voltage, not total power. DC and inverter drives must control full motor current. This means that the ECD control does not require the high power semi-conductors which are so troublesome to other drive types.

CONTROL INTERCHANGEABILITY
     Due to the small amount of control power required to control the drive (typically 2% of motor HP), only one size solid state control is used form 1 to 150 HP. Thus, availability and interchangeability are optimized. Requirements for spares are minimized where two or more drives of different sizes are installed in the same location.


REMOTE OPERATOR STATIONS
      The basic operator station is furnished with run and stop pushbuttons and a speed setting potentiometer. Operator stations can also be modified to contain a vast assortment of other features as demanded by application requirements.

BRAKE CONTROL
      When either friction (non-failsafe) or Eddy Current Clutch Brakes are provided, the adjustable braking option must be included in the ECD control to provide adjustable braking torque.

DUAL CHANNEL CONTORL FOR EDDY CURRENT CLUTCH-BRAKES
      When an Eddy Current Clutch-Brake is supplied for overhauling loads or to improve dynamic response in deceleration, a "dual channel" controller is required. Regulation of 1% of maximum speed is provided over the entire speed range by overlapping the coupling and brake coil adjustments to provide "no backlash" control.

CONTROL OPTIONS
      The basic ECD control is arranged to accept most control options within the basic control enclosure. Slide track mounting and terminal connections allow easy conversion of the basic controller to suit most applications. Options most commonly provided include:
  • Jog - Permits intermittent operation at a separate adjustable speed by pushing and holding a separate jog push button.
  • Thread - Applications in paper, textile, plastic, steel and other industries often require special selected slow speed for initially feeding or threading material through the driven equipment. Same as jog control, but drive does not stop until stop button is pushed.
  • Signal Follower - Permits drive to follow a remote signal (voltage, current, process variables, etc.) and adjusts speed or torque as required based on a pre-determined relationship.
  • Torque Limit - Provides maximum limit on torque transmitted by sensing motor current (adjustable 80-150% motor rating) or by limiting maximum voltage applied to coupling coil - adjustable 25-100% off rated load.
  • Acceleration/Deceleration - Linear acceleration control is supplied as standard on all our drives. It provides a smooth, uniform speed increase during starting or when speed is increased. Adjustable 2-20 seconds. Linear acceleration/deceleration permits uniform speed change during starting ands topping and during speed increase and decrease. Separately adjustable rates 2-25 seconds. Note: Sufficient braking torque must be provided by load, or Eddy Current Brake must be provided for deceleration control to properly function.

    OTHER CONTROL MODIFICATIONS
          A wide variety of other control modifications is also available, which allows engineering of a controller to meet your specific requirements.