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The Vari Speed® R400 is a full-wave DC regenerative control that provides high performance four quadrant speed and torque control. The R400 solid state controller converts single phase AC line power into an adjustable DC power to control 1/4 to 2 horsepower DC motors.

The R400's flexible design is easily selectable for speed or torque mode, tachometer voltage, dual voltage and for horsepower size. The R400 is designed with today's most desirable features including isolated input signals, status indicators, alarm outputs. When performing frequent directional changes, the R400 transfers excess system energy back to the AC line rather than wasting additional energy by the use of a dynamic brake resistor.

The R400 is designed, engineered and manufactured in the USA, and is UL and cUL listed.

Regenerative (Four-Quadrant) Control

Regenerative DC drives are able to provide complete control of a DC motor's speed and torque simultaneously. A regenerative drive has the capability of producing torque in either braking or motoring modes, while operating a motor's speed in a consistent direction of rotation. The capability to provide braking torque is a result of the drive's ability to operate in all for quadrants of the motor's speed/torque curve.

A four-quad DC drive's ability to operate in a regenerative mode is primarily provided by the additional power section included in the design. Four additional SCR devices are utilized in comparison to a standard NEMA Code K-type converter. These four additional components allow for the complete control of both the voltage and current flow to the armature of the DC motor, thus controlling both the speed and torque.

Standard Product Feature Application Benefit
Multiple rated unit One unit can be used for 120 or 240 VAC operation of 1/4 to 2 HP PM or wound field DC motors
Regenerative control Allows 4-quadrant operation to maintain complete control of motor and load
Speed or torque control Provides proper motor control for application requirements
Excellent regulation performance Improves overall system operation
Fast acting current limit Can quickly react and compensate to load changes
2- or 3-wire start/stop Provides flexibility in system logic
Isolated logic inputs Easy connection of peripheral equipment
Alarm output Provides remote indication of an undesirable situation
Status indicators Visual indication of primary control status
150% load capabilities Extra power for intermittent overloads
Reversible Simple external contact closure or + or - 10VDC for motor shaft rotation reversing


  • Excellent regulation performance
  • Fast acting current limit
  • Starts into a rotating motor
  • 50 or 60 Hz selectable
  • Provides 150% load for one minute
  • Two and three-wire start-stop
  • Disable function
  • Reversible


  • Food and beverages
  • Machinery and material handling
  • Packaging and chemicals

Chasis Version
Part No.
120 or 240 VAC selectable 176B4000
120 or 240 VAC selectable, with field supply 176B4001
120 or 240 VAC selectable, 1/100 - 1/20 hp 176B8013

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Download Catalog Pages:
r400.pdf ( 709KB )
Download Instruction Manual:
r400.pdf ( 2.14MB )

Control Parameters
Factory Settings
Line Voltage (1Ř) VAC ±10%
Line Frequency (Hz)

120 or 240
50 or 60

PLC or Process Input
Follow Voltage (VDC)
Speed and Torque Potentiometer (Kohm, 1/4 W)
Remote Two or Three Wire Start-Stop
Tachometer @ 1,000 RPM (VDC)

7 or 20.8

Armature Current Max (Amps, DC)
Motor Rating at 120 VAC (HP)
Motor Rating at 240 VAC (HP)
Armature Voltage at 120 VAC (VDC)
Armature Voltage at 240 VAC (VDC)
Field Voltage at 120 VAC (VDC)**
Field Voltage at 240 VAC (VDC)**
Field Current at 120 VAC (Amps)**
Field Current at 240 VAC (Amps)**
Service Factor
Overload for One Minute (%)
Start/Stops per Minute (Max) @ Full Load1
@ Speed Change 100%

10.8 (2.0)
1/4 - 1 (1/30 - 1/8)
1/4 - 2 (1/30 - 1/8)
0 ±100
0 ±200
1 (nominal)
1 (nominal)





Forward Acceleration Rate (sec)
Reverse Acceleration Rate (sec)
Minimum Speed/Torque (%)
Maximum Speed/Torque (%)
Forward Current Limit (%)
Reverse Current Limit (%)
IR Compensation (%)
Dynamic of Loop Regulation

0.15 - 8
0.15 - 8
0 - 50
50 - 110
0 - 150
0 - 150
0 - 25

1Reflected inertial 10.7 lb.in2 at 1HP motor (55°C ambient temperature).
*( ) For 176B8013
**176B4001 only