ALL-TEST
PRO
®
31 User Manual
©2011, ALL-TEST
Pro,
LLC
www.alltestpro.com
rev 2011-11F
34
TRENDING
Series Motor-Connect the instrument test leads to A1 & S2, record and trend Impedance, Phase
angle and I/F. Impedance reading will vary with temperature, and is important that comparative
reading are taken at the same temperature. If the impedance is decreasing with time the armature
winding are either contaminated or degrading. Changes in phase angle and I/F signify winding
shorts.
ASSEMBLED
1.
Connect the instrument test leads to the A1 and A2 armature leads.
2.
Lift all but two of the DC motor brushes 90 degrees from each other.
3.
Select the Motor Test from the main menu
(see Winding Test section)
.
4.
Adjust the test frequency until you are between 1 and 999 Ohms of impedance.
5.
Position the leading edge of one of the brushes at the edge of one rotor bar. Note the impedance
and phase angle values.
6.
Repeat step 6 until you have completed one full revolution.
7.
If the impedance values are consistent and/or repeating, the armature is good. If not, there is a
short.
Note: This test can also be performed using I/F (Screen 2) and % Deviation (Screen 3).
DISASSEMBLED
1.
Connect the instrument ATF 1100 Armature Test Forks.
2.
Select the Motor Test from the main menu
(see Winding Test section)
.
3.
Separate the Armature Test Forks to approximately 90 degree span of the commutator. Lock the
test fork span by tightening the locking handle on the test fork. (If the commutator is too large
expand the test forks to their maximum dimension).
4.
Mark one of the commutator segments as the starting point.
5.
Place one of the test forks on the marked commutator segment; place the other test fork on the
commutator segment determined by step 3 above.
6.
Adjust the test frequency until you are between 1 and 999 Ohms of impedance.
7.
Read and record the impedance value from the ALL-TEST PRO 31 display screen.
8.
Repeat step 6 until you have completed one full rotation around the commutator.
9.
If the impedance values are consistent and/or repeating, the armature is good. If not, there is a
short.
Note: This test can also be performed using I/F (Screen 2) and % Deviation (Screen 3).
DC Motor Analysis
DC field coil analysis is performed by using one of three methods:
1.
Trend
– Trend the windings over time or compare to a past reading. The Fi and I/F readings
should be within one digit from the baseline reading.
2.
Compare
– Two similar DC motors (same manufacturer and model) can be compared to each
other. The Fi and I/F readings should be within one digit of each other.
