• The Dart 250G Series variable speed DC motor control is a versatile, general purpose control rated to 2 HP, available in
chassis mount or enclosed configurations; with options for specific applications.
• The 251G model is available with an adjustable HP range of 1/50 thru 1/8 at 120 VAC input.
• The 253G model has a dual voltage input (may accommodate either 120 or 240 VAC). It is available with an adjustable HP
range of 1/8 thru 1 HP for 120 VAC, and 1/4 thru 2 HP for 240 VAC input.
• Designed for DC Permanent Magnet, Shunt Wound, and some Universal (AC/DC) motors in the above horsepower ranges.
• Incoming AC voltage is also converted to adjustable full wave rectified DC voltage (via a packaged bridge) to operate the DC
motor. Also, a full wave field voltage is provided for shunt wound motors (see page 4 for voltages).
• The control incorporates transient voltage protection with adjustable current limit and an AC fuse for protection. It
features adjustable minimum and maximum speeds along with adjustable acceleration and IR Compensation. Tach feedback
is accomplished thru a connection to a pin (P2) on the printed circuit board.
• The 250G Series has a linear acceleration/deceleration ramp.
• The control also has a barrier type terminal strip for all power and control wiring.
• The enclosed model uses a gasketed cover assembly that is rated NEMA 4/12.
• cULus Listed.
MIN. SPEED (minimum speed) - Allows adjustment of the motor speed when the speedpot is set at minimum (CCW). This
permits the user to eliminate the "deadband" on the main speed control permitting zero calibration. Clockwise rotation of "MIN"
trimpot increases minimum motor speed.
MAX. SPEED (maximum speed) - provides for adjustment of the motor speed when the speedpot is set at maximum (CW). This
permits the user to eliminate the top end "deadband", which will provide full speed at maximum rotation. Rotation of the "MAX"
trimpot in the clockwise direction increases the maximum motor speed.
ACCEL (acceleration) - allows adjustment of the motor acceleration from a minimum of 0.5 seconds to approximately 8.0 sec-
onds. The deceleration time depends on the ACCEL setting. For DECEL time equal to ACCEL time, see -17B option.
IR COMP (speed regulation) - adjusts the control output to compensate for speed changes caused by varying motor loads. As
the motor load is increased, IR COMP increases the voltage output of the control. Clockwise rotation of the "IR COMP" trimpot
will increase compensation.
CUR. LIM. (current limit) - provides protection from excessive armature current by limiting the maximum armature current the
control can provide. This enables adjustment of the maximum torque the motor can deliver. Current limit adjustment (CUR LIM)
is set at 125% of the rated motor current (torque) based on horsepower. Clockwise rotation of the "CUR LIM" trimpot increases
the current (torque) the control will provide.
INHIBIT TERMINAL PIN (P2) - allows the user a choice of stopping and starting hard (fast) or stopping hard with a soft start
through an adjustable acceleration ramp, without breaking the AC lines (see page 8).
TERMINAL STRIP - allows for connection of AC lines, motor leads, motor field (if needed), and speed potentiometer.
FOR CHASSIS VERSION: Allow 1.55" for height clearance, 7.00" for overall length.
FOR ENCLOSED VERSION: Allow 3.50" for height clearance, 7.40" for overall length.
INTRODUCTION
CONTROL FEATURES
HEATSINK DIMENSIONS
5.530
7.000
5.500
.750
7/32 SLOTS (4)
TYP. .350 DEEP
2
5.125