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Pplication, Roubleshooting, Alibration – Red Lion PAXLIT User Manual

Page 6

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CAUTION: It is recommended that the current transformer be
internally protected or that a voltage clamping circuit be provided,
preventing dangerous high voltage across the CT secondary
windings in case of accidental opening of the secondary output
leads when the primary is energized.

In order to prevent risk of electric shock ensure CT is installed

according to local NEC regulations for installation of current
instrument transformers.

6

PROBLEM

REMEDIES

NO DISPLAY

CHECK: Power switch and line voltage

INCORRECT DISPLAY

OVER-RANGE INDICATION

VERIFY: Input signal

CHECK: Scaling adjustment pot DIP switch position
ADJUST: Scaling pot
VERIFY: Input Signal

For further assistance, contact technical support at the appropriate company numbers listed.

MOTOR CURRENT MEASUREMENT USING A
CURRENT TRANSFORMER

The PAXLIT 5 Amp AC Current Meter is configured by simply connecting

the “COMM.” (Terminal 3) and the “5AMP” (Terminal 4) to the external
current transformer. The current carrying wire to be sensed is passed through the
center of the current transformer. The resolution of the display, in this case, is
0.1 Amp, therefore, “Switch #1” is selected.

The meter is now ready to be scaled. The installer has access to a calibrated

portable digital current meter capable of measuring the motor current. Scaling
will be accomplished by adjusting the scaling pot on the PAXLIT meter to agree
with the portable digital current meter. The operator turns on the AC motor and
lifts a large weight to load the motor. The installer then simply adjusts the
scaling adjustment, located at the rear of the unit, until the display is equal to
the value indicated on the portable current meter. The meter will now indicate
the load current of the motor precisely.

5.0 A

PPLICATION

9

1

3

2

4

5

6

7

8

10

AC

CRANE
MOTOR

CURRENT TRANSFORMER
200 AMP/5 AMP RATIO

SCALE

ADJUST

115V/230V

6.0 T

ROUBLESHOOTING

7.0 C

ALIBRATION

The meter has been fully calibrated at the factory. Scaling to convert the input

signal to a desired display value is performed by enabling the scale pot
DIP switch. If the meter appears to be indicating incorrectly or inaccurately,
refer to Troubleshooting before attempting to calibrate the meter.

When recalibration is required (generally every two years), it should only be

performed by qualified technicians using appropriate equipment.

Input Calibration

Before starting, verfiy that the precision signal source is connected and ready.

Allow a 30 minute warm-up period before calibrating the meter.

Then perform the following procedure:

1. Set the DIP switch off to disable the scaling pot.
2. Apply half scale input signal.
3. Adjust calibration potentiometer as necessary for the display to read 1000

(ignore decimal point)

4. Apply zero signal and ensure display reads zero.
5. Apply full scale signal and ensure display reads 1999.

WARNING: Calibration of this meter requires a signal source

with an accuracy of 0.05% or better and an external meter with
an accuracy of 0.005% or better.