Instructions

Table Of Contents
RONK ELECTRICAL INDUSTRIES, INC. PH: (217) 563-8333 MAN3081
the circuit by the run assist contactor. This increases the manufactured phase’s current output to
match the motor’s higher load condition.
1. When high load conditions are sensed by the board, the run assist contactor is energized,
adding the run assist capacitors in parallel with the main bank of run capacitors. This
additional capacitance raises the “A” phase current output. The higher “A” phase output helps
balance the currents when the motor operates under higher load conditions.
2. When the load conditions are reduced, the circuit board will de-energize the run assist
contactor. This removes the run assist capacitors from the circuit, which brings the “A” phase
current back down to its normal operating level.
AUTO ADJUST CIRCUIT BOARD
The circuit board performs two different functions. It controls the initiation of the converter’s start
circuit. It also controls the run assist contactor.
CURRENT TRANSFORMER (C.T.)
The C.T., which senses the amount of current in the “C” phase
output wire, provides a signal to the circuit board that is directly proportional to the “C” phase current.
CONTROL CIRCUIT BOARD
The circuit board uses the C.T. signal for its two sensing circuits. The
first circuit senses when the motor is operating, and the second circuit senses the load on the motor.
1. The auxiliary relay that powers the start circuit is energized by the control board when the “C”
phase current rises above 5-10 amps. The auxiliary relay remains energized while the motor
runs. When the motor shuts off, the auxiliary relay is de-energized, which “resets” the start
circuit. An indicating LED, located on the right-hand side of the board, illuminates when the
current is above the auxiliary relay’s “pull in” level.
2. The second function of the circuit board is to control the run assist contactor. The contactor is
energized when the board senses an increase in load above the motor’s normal operating
range. When the board senses that the load has returned to its normal operating range, it will
de-energize the run assist contactor. The “pull-in” and “drop-out” points are preset at the
factory. An indicating LED in the front center of the board is illuminated when the current is
above the “pull-in” level.
ADJUSTMENTS
The potentiometers that set the amperage level where the sensing circuits “pull-in” and “drop-out” are
preset for the expected load conditions at the factory. If load conditions are not as expected, the
board can be adjusted for those conditions with assistance from RONK. Contact RONK before
making any adjustments to the circuit board.
BALANCING
The Auto Adjusting ADD-A-PHASE units generally do not require balancing, but sometimes load
conditions are not as expected and current imbalance is greater than wanted. You will need the
amperage readings (identified “A” (L3), “B” (L2), and “C” (L1) as labeled in the ADD-A-PHASE), serial
number of the ADD-A-PHASE, and motor nameplate information for us to assist you. Use the Data
Recording Sheet provided to record this information. Identify whether the run assist contactor is in or
out (or both). This information is necessary for us to give you immediate assistance with balancing or