Starting Out
25
QPAC User's Manual
How to Operate QPAC, Chapter 3
Operation
Setup Adjustments
After the QPAC is installed and wired it may need a few minor adjustments. The
three phase power controls require that proper phase rotation exists. QPACs
that use the BF, BV, AF or AL Control Cards may need minor bias and gain
calibrations. QPACs that use the AL Phase Angle Current Limit Control Card
will need current limit calibration. Refer to the following paragraphs.
Phase Rotation Adjustment for Q32 and Q33
Three phase QPAC SCR controllers require the correct phase sequence of the
attached line voltage. To check for proper phase sequence of the QPAC-32
power control, measure the voltage from T1 to T2, T2 to T3 and T3 to T1 with
the power control turned full ON. If any of the measurements of output voltage
are not equal (within 10%), exchange any two of the power input lines (L1 and
L2) to the QPAC.
To check for proper phase sequence of the QPAC-33 power control, apply
power to the QPAC and observe the LED indicators in the upper left hand corner
of the Power Base motherboard. If the phase rotation LED is not illuminated,
exchange any two incoming power lines (L1 and L2).
Bias And Gain Adjustments for AF, AL, BF, BV
Bias and gain can be adjusted to interface with the output of most standard
temperature controls with a proportional output. Bias and gain is factory set for
an input control signal of 4-20mA but can be adjusted over a range of 0-12VDC
or 0-25mA to match the output of a specific temperature control. Input imped-
ance for 4-20mA input is 250Ω. The input impedance can be changed to 5KΩ to
accept a voltage by performing the following procedure for each card.
Voltage Input Conversions
AF (08-5288): For 5KΩ input, move J2 jumper, located on the lower left of the
AF card next to the TB-2 connector, Terminal 5. See Figure 34.
AL (08-5411): For 5KΩ input, replace the J2 jumper to the 5V position,
located on the lower left of the AL card to the 5V position. See Figure 37.
BF (08-5289): For 5KΩ input, remove resistor R3, located on the lower left of
the QBF card next to the TB-2 connector, Terminal 5. See Figure 35.
BV (08-5342): For 5KΩ input, remove the external resistor attached to the J3
connector plug. See Figure 36.
Adjustment Procedure:
We recommended that bias and gain adjustment be performed using a dummy
load. In some applications, a dummy load may be required if the controlled load
can not be turned full ON. A dummy load can be easily made by connecting 150
watt lamps in series to match the operating voltage of the QPAC. Use the
following steps to make adjustments.
Chapter 3
How to Operate the QPAC
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