GE VAT20 - Motor Overheat Troubleshooting; Disturbing Motor Operation Troubleshooting

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(2) Motor over-heat
Is there
anything that might
affect motor
cooling?
Reduce loading
Enlarge VAT20 and
Motor capacity
Is the
voltage level between
T1-T2, T2-T3, and T3-T1
normal?
YES
Operate at low
speed for a long time?
Select another motor
Remove obstacle
affecting motor cooling
Correct the connection
NO
YES
YES
VAT20 malfunction
Poor connection
between VAT20 and
motor
Is
there over-loading
condition or the load current
exceeds rated
current?
NO
YES
YES
NO
NO
(3) Disturbing motor operation
Is there
any excess vibration
at transmission parts
like gears?
Increase or decrease
acceleration /
deceleration time
Is there any loading
variation condition?
YES
Reduce load Increase
VAT20 and motor
capacity
Reduce loading
variation or install
fly wheel
Improve mechanical
system
NO
YES
YES
VAT20 malfunction
During acceleration or
deceleration ?
NO
Is the
voltage level
between T1-T2, T2-T3, and
T3-T1 normal?
Is the
acceleration/
deceleration time setting
appropriate?
VAT20 malfunction
NO
NO
Not
appropriate
Appropriate
YES (The differences between different wires are within +-3%)