# Phase analysis motor in vacuum

Messrs. Forum, good day, thank you for your support in terms of the diagnosis of phases made to an electric motor in vacuum (uncoupled from the pump that drives) which has been diagnosed imbalance in the rotor of the engine when it was in operation coupled to the bomb.

According to what has been seen, there is no imbalance (phases of the vacuum motor uncoupled from the pump):
- Horizontal Phasing Difference = 111 °
There is no static or coupe imbalance.
- Vertical Pitch Difference = 123 °
There is no static or coupe imbalance.
- Difference of Phases Horizontal / Vertical of the free side = 139 °
There is no static or coupe imbalance.
- Difference of Phases Horizontal / Vertical of the fixed side = 177 °
There is no static or coupe imbalance.
- Difference of Axial Phases = 175 °
Indicates misalignment due to the fact that there were grooves in the bearing (fixed side).
From the foregoing, no imbalance is observed in the motor rotor.
Best regards and successes.
Original Post
John from PA posted:

Amplitudes?

The amplitudes taken with the motor in vacuum (uncoupled from the pump) are:

horizontal (free side) = 1.2 mm/s
vertical (free side) = 1.5 mm/s
horizontal (fixed side) = 2.5 mm/s
vertical (fiji side) = 2.25 mm/s
Best regards and successes.
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MARCO20002000 posted:
John from PA posted:

Amplitudes?

The amplitudes taken with the motor in vacuum (uncoupled from the pump) are:

horizontal (free side) = 1.2 mm/s
vertical (free side) = 1.5 mm/s
horizontal (fixed side) = 2.5 mm/s
vertical (fiji side) = 2.25 mm/s
Best regards and successes.

According to axial phase differences if you  put the sensor at the same direction , it seem you have bend shaft .how much the axial vibration amplitude ?

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aziz58 posted:
MARCO20002000 posted:
John from PA posted:

Amplitudes?

The amplitudes taken with the motor in vacuum (uncoupled from the pump) are:

horizontal (free side) = 1.2 mm/s
vertical (free side) = 1.5 mm/s
horizontal (fixed side) = 2.5 mm/s
vertical (fiji side) = 2.25 mm/s
Best regards and successes.

According to axial phase differences if you  put the sensor at the same direction , it seem you have bend shaft .how much the axial vibration amplitude ?

Good morning, the axial amplitude is 2.8 mm/s in the fixed side and it found loose in the bearing of this side and the axial amplitude in the free side is 1.5 mm/s.

Best regards and successes.

()
MARCO20002000 posted:
aziz58 posted:
MARCO20002000 posted:
John from PA posted:

Amplitudes?

The amplitudes taken with the motor in vacuum (uncoupled from the pump) are:

horizontal (free side) = 1.2 mm/s
vertical (free side) = 1.5 mm/s
horizontal (fixed side) = 2.5 mm/s
vertical (fiji side) = 2.25 mm/s
Best regards and successes.

According to axial phase differences if you  put the sensor at the same direction , it seem you have bend shaft .how much the axial vibration amplitude ?

Good morning, the axial amplitude is 2.8 mm/s in the fixed side and it found loose in the bearing of this side and the axial amplitude in the free side is 1.5 mm/s.

Best regards and successes.

Can u post spectrum?

Also u can get axial phase of housing bearing to check of cock bearing

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MARCO20002000 posted:

Messrs. Forum, good day, thank you for your support in terms of the diagnosis of phases made to an electric motor in vacuum (uncoupled from the pump that drives) which has been diagnosed imbalance in the rotor of the engine when it was in operation coupled to the bomb.

According to what has been seen, there is no imbalance (phases of the vacuum motor uncoupled from the pump):
- Horizontal Phasing Difference = 111 °
There is no static or coupe imbalance.
- Vertical Pitch Difference = 123 °
There is no static or coupe imbalance.
- Difference of Phases Horizontal / Vertical of the free side = 139 °
There is no static or coupe imbalance.
- Difference of Phases Horizontal / Vertical of the fixed side = 177 °
There is no static or coupe imbalance.
- Difference of Axial Phases = 175 °
Indicates misalignment due to the fact that there were grooves in the bearing (fixed side).
From the foregoing, no imbalance is observed in the motor rotor.
Best regards and successes.

From the above  Phase analysis details.

1. Phase shift was in between 90* - 180*, which could be a losseness, Housing looseness, crack damage, Bend shaft or even a Rigidity issue. Amplitudes will support furrther to analyse.

Thanks

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My general rule of thumb is that if phase difference is greater than +/- 90-degrees, then motion is out-of-phase. I therefore do not agree with the OP statement that there is no couple unbalance.

"From the foregoing, no imbalance is observed in the motor rotor."

The vibration levels are low, but you do not state what is your vibration or residual unbalance criteria to support your conclusion.

Walt

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OP,

How are you making all of the vibration measurements at many locations-directions with motor in a vacuum?

Walt

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