ALL-TEST PRO AT31, Руководство пользователя

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ALL-TEST
PRO ®
31 User Manual
©2011, ALL-TEST
Pro,
LLC
www.alltestpro.com
rev 2011-11F
22
Rotor Test
Squirrel Cage Induction motors operate on the magnetic inductance principle. The rotor bars provide the
path for the current to flow on the rotor. The current flow through the rotor bars creates a magnetic field
which in turn causes the rotor iron to become a very strong electro-magnet. If rotor bars are open,
broken or have large casting voids, current will not flow properly through the rotor bars. This causes
unbalanced magnetic forces applied between the rotor and the stator, low operating torque and could
eventually created physical contact between the rotor and the stator.
The ALL-TEST
PRO®
31 provides a feature that performs
2 unique quick rotor tests
to determine if
any rotor issues are present in an assembled induction rotor. Rotor issues such as broken or loose rotor
bars, casting voids in the cast aluminum rotors, eccentrically machined rotors and high resistance
connections are some of the rotor issues easily recognized by the ALL-TEST
PRO®
31.
Bar Test
: Provides a visual “real time” indication of the response of the rotor to the energized
stator field.
Waveform Test
: Provides an additional visual indication of the change in response of the rotor
to the energized stator field in the shape of a time wave form.
Both rotor tests send a low voltage AC sine wave signal through the stator winding and manual rotation
of the shaft induces a voltage into the rotor bars.
The ALL-TEST
PRO®
31 measures and displays the interaction between these 2 magnetic fields. A
rotor without issues should provide a symmetrical and repeatable display. Induction rotors with issues
will provide erratic, distorted displays. Additional tests are recommended to assist in determining the
exact cause of the rotor issue.
Bar Test
1. Use the ON key or the MODE key on the keypad section to turn the instrument on and access the
main menu
2. Connect the instrument leads to any 2 motor leads
3. Use the ◄►to highlight the ROT icon screen
4. Depress the ZERO/OK key. The “Bar” Rotor Test will begin