Troubleshoot AC Motors – Part 3
This is a 4 part series, click to view each part: 1 : 2 : 3 : 4
Problem C – Motor overheats
| C1: Is ambient temperature too high? |  | Reduce ambient, increase ventilation or install larger motor. |
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| C2: Is motor too small for present operating conditions? | | Install larger motor. |
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| C3: Is motor started too frequently? | | Reduce starting cycle or use larger motor. |
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| C4: Check external frame. Is it covered with dirt which acts as insulation and prevents proper cooling? | | Wipe, scrape or vacuum accumulated dirt from frame. |
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| C5: Feel output from air exhaust openings. Is flow light or inconsistent indicating poor ventilation? | | Remove obstructions or dirt preventing free circulation of air flow. If needed, clean internal air passages. |
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| C6: Check input current while driving load. Is it excessive indicating an overload? |  | Go to Step C11. |
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| C7: Is the driven equipment overload? | | Reduce load or install larger motor. |
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| C8: Are misalignments, bad bearings or damaged component causing excessive friction in driven machine or power transmission system? | | Repair or replace bad components. |
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| C9: Are motor bearings dry? | | Lubricate. Does motor still draw excessive current? |
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| C10: Are damaged end bells, rubbing fan, bent shaft or rubbing rotor causing excessive internal friction? | | Repair or replace motor. |
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| C11: Are bad bearings causing excessive friction? | | Determine cause of bad bearings (See Problem D). |
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| C12: Check phase voltage. Does it vary between phases? | | Restore equal voltage on all phases. |
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| C13: Is voltage more than 10% above or 10% below nameplate? | | Restore proper voltage or install motor built for the voltage. |
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| C14: Check stator. Are any coils grounded or shorted? | | Repair coils or replace motor. |
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