Four quadrant control of DC Motors
Model 2748D Digital
Model 2748A Analog
Isolated Input

  • 10 Bit digitial input, or
• ±5 VDC analog input
• 1500 volt isolation (minimum)
• Full-wave four-quadrant CD output
• Opto-isolated failsafe input

  DESCRIPTION:
  POWR UPS Model 2748A and 2748D motor controls are full wave, full regenerative (four quadrant), completely self contained units that control the speed and direction of motor torque of 24 VDC permanent magnet (PM) DC motors. Direction switching is fully static (solid state). Model 2748 is an exceptionally rugged unit that incorporates thyristor phase angle control. Delivered output ranges to 2 amperes at 24 VDC. Less expensive and more rugged than PWM servo amplifiers, these controls are ideal for small velocity or position control applications, and replace costlier and less rugged PWM amplifiers in many applications.

Model 2748 units are available in open frame construction, suitable for OEM use in user provided enclosures. Power connections are made using a heavy duty barrier block. Signal connections use a lighter duty barrier block. Both blocks are field removable. Mounting holes are provided for either bottom or edge mounting.

Model 2748 controls operate from a nominal 115 VAC, 60 Hz line. A power line fuse is incorporated on the mounting base plate. These controls are completely self contained and include an internal power supply transformer to drive motors with an armature rating of 24 VDC.

ANALOG INPUT: Model 2748A analog input controls are designed to be easily interfaced to low level analog circuitry. Signal input signals are isolated from the motor and power line with a minimum isolation voltage of 1500 VDC. This reduces the possibility of grounding, noise or safety problems. The motor speed and direction are determined by the amplitude and polarity (5 volts full scale) of the input signal. In addition, a failsafe circuit de-energizes the motor if the input control power is not present.

DIGITAL INPUT: Model 2748D digital input motor controls are designed to be easily interfaced to microprocessors or 10 bit parallel TTL logic level sources. Speed resolution is 9 bits, and one bit is used for direction. For lower resolution, unused bits may be tied off. Logic input signals are isolated from motor and power line with a minimum isolation voltage of 1500 VDC. This reduces the possibility of grounding, noise or safety problems. The motor speed and direction are determined by the value of a ten bit parallel input which consists of one bit for direction, and 9 bits for motor speed. In addition, a failsafe circuit de-energizes the motor if the input control power is not present.

Options
Plug in adjustable Accel/Decel board permits clockwise and counterclockwise control of acceleration and deceleration with four independent adjustments (p/n 2745-06).

Plug in optical encoder, electronic brake and Accel/decel board permits four independent adjustments for high precision speed regulation, electronic acceleration and deceleration.

Perforated metal cover (2748 COVER).