Mechanical
Influences - Case History 2 Coal Conveyor Motor Drive |
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Test
Objective
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Nameplate
details
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Additional
Information
It was not known whether it was a 2 or 3 stage reduction gearbox - hence additional mechanical influences may exist. At
full load the current components at the following
frequencies can occur around the 50 Hz component: Motor opertating at reduced load Actual
input current = 130 A Author's prediction of operational slip (±10%) at reduced current = 0.0066, Actual Motor Speed = 1490 r.p.m., therefore sidebands due to broken bars = ±0.66 Hz |
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MCSA
Expert Analysis of Coal Conveyor Drive Train
The ammeter
reading was relatively steady compared to the previous Coal Crusher (Mill)
motors (Mechanical Influences Case History 1) hence the smearing effect
in the spectrum should not be so nearly pronounced. |
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Expert
Comment There are no sidebands due to broken bars in the region of ± 0.66 Hz. All the current components in Figures m-6 and m-7 are due to mechanical disturbances on the rotor from the gearbox/conveyor.
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EM
Diagnostics Ltd, |
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