DC Drives: An Example

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Regenerative DC Drive
above: Regenerative DC drive from Polyspede, Model PRD12B-401B. Click image for more detail.


This drive offers full features in a cost-saving half-wave design. The PRD powers industrial DC motors for starting, stopping, reversing, accelerating or braking in either direction.

When a PRD regenerative control is signaled to brake the mechanical load, it causes the motor to act as a generator. The braking energy is sent back into the AC power lines, eliminating the need for heat-producing dynamic braking resistors. Besides simplifying the overall installation, the PRD also provides faster braking than is possible with non-regenerative controls.

A PRD control is an ideal choice for: high-duty cycle indexing and reversing; controlling high inertia loads; also hoisting or other applications requiring controlled hold-back torque.

The unique circuit design provides a 4 to 6 Hz velocity and torque loop response in the PRD. There are no overshoots during acceleration, deceleration or reversing.

The PRD interfaces easily with programmable controllers, or directly with process instruments that provide an analog signal output

Specifications of the PRD12B-401B DC Drive:

Input: 460VAC, Three Phase

Output: 500VDC Armature; 300VDC Field; 40 HP

1.0 Motor/Load Type: DC Motor
2.0 Rating:
2.1 Horsepower: 40
2.2 Armature: 0 ~ 500 VDC
2.3 Field: 300/480 VDC
3.0 Rated Input:
3.1 Input Voltage: 380 - 480VAC ±10%
3.2 Phase: 3
3.3 Frequency: 50/60 ±5%
4.0 Rated Output:
4.1 Voltage: Arm: 500VDC, Fld: 300VDC
5.0 Overload Capacity: 150% for one minute
6.0 Acceleration / Deceleration: Optional
7.0 Speed Regulation:
7.1 Armature Feedback: ±1.0%
7.2 Tachometer Feedback: ±0.1%
8.0 Control Method: Regenerative
9.0 Mechanical Properties:
9.1 Height: 18.5 inches (470mm)
9.2 Width: 16 inches (406mm)
9.3 Depth: 6.4 inches (163mm)
9.4 Weight: (lbs) 21
10.0 Options: Acceleration/Deceleration (Linear) - $92 Acceleration/Deceleration (S-Curve) - $172 Position Interface - $172 Adjustable Jog - $59 Field Ecnomizer - $98 External Signal Follower - $149 External Voltage Follower - $123 Field Weakening - $1033 Contactor - $196 NEMA 12 Enclosure - $571

Connections for DC drive
Above: Connections for DC drive. Click image for more detail.

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