User's Manual - Minarik

4Regenerative DrivesMost non-regenerative, variable speed, DC drives controlcurrent flow to a motor in one direction. The direction ofcurrent flow is the same direction as the motor rotation.Non-regenerative drives operate in Quadrant 1, and also inQuadrant 3 if the drive is reversible (Figure 3). Motors muststop before reversing direction. Unless dynamic braking isused, non-regenerative drives cannot oppose an overhaulingload, and cannot decelerate a load faster than coasting to alower speed.Regenerative drives operate in two additional quadrants:Quadrant 2 and Quadrant 4. In these quadrants, motor torqueis in the opposite direction of motor rotation.Regenerative drives can reverse a motor without contactors,switches, brake resistors, and inhibit plugs. They can alsocontrol an overhauling load and decelerate a load faster than itwould take to coast to a lower speed.The RG25U and the RG51UA are regenerative drives. Theyare uncased chassis model drives and designed to be installedin original equipment. The drives are the same electrically.The physical layout and size of these drives are different (seeDimensions section). The RG51UA includes a field supply forshunt wound motors.The RG25U and the RG51UA are half wave rectified DCregenerative drives. Therefore the maximum armature voltage