Amprobe PRM-4 Phase-Sequence-Motor-Rotation-Tester - Manual (Page 8)

7
MAkINg MEASUREMENTS
3-Phase Rotation Test
�� Caution
This instrument only indicates that voltage is present, not the
voltage level. Verify the actual voltage with a multimeter. Using the
wrong voltage can damage a motor.
Connect the three color coded test leads to the 3-phase input 1.
terminals, l1-l2-l3 also know as A-B-C or R-S-T. See figure 1.
Connect the three color coded alligator clips to the terminals of
2.
a 3-phase power source. The connection order is optional. Use
extreme caution in this high voltage situation.
Confirm that all three lights below the test lead inputs on the
3.
PRM-4 are on. if one or more of the three lights is off, there is an
open phase condition. Correct the power source problems before
proceeding (See open Phase Test later in this manual). if the open
Phase tests are good, the PRM-4 is defective. Repair or replace the
PRM-4 before proceeding.
if all three lamps are on, check the phase rotation indication for
4.
the rotation direction, clockwise (�) or counter-clockwise (�)
indicator.
if the counter clockwise lamp is on, reverse the connections of any
5.
two of the three alligator clips for clockwise rotation. Use extreme
caution in this high voltage situation.
The phase sequence is correct for clockwise (
6. � ) rotation when
the clockwise lamp is on and the power source terminals are
connected by the alligator clips to l1, l2, and l3. Remove power
and label the power source wires.
open Phase Test
�� Caution
The multimeter used for this test should be properly rated for the
circuit under test.
Connect a multimeter (set to VAC and the voltage range expected) 1.
V input to the phase wire in question and the CoM input to
neutral or ground to check the phase voltage. Use extreme
caution in this high voltage situation.
Verify that the two other phases are working properly and that
2.
the 3-phase to phase voltages are correct. if a problem is found,