Motor Trouble Shooting Guide (General)
Problem | Possible Causes | Corrective Actions | |||
High current draw (all 3 phases) | 1. | Low line voltage (5 to 10% lower | 1. | Consult power company. | |
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| than nameplate). | 2. | Change to 230V motor. | |
| 2. | 200V motor on 230/240V system. | |||
| 3. | 230V motor on 208V system. | 3. | Change to 200V or 280V motor. | |
| 4. | Incorrect propeller. | 4. | Consult factory. | |
| 5. | Incorrect pitch if adjustable | 5. | Reduce pitch / consult factory | |
Low motor current draw | 1. | Incorrect propeller. | 1. | Consult factory | |
| 2. | Incorrect pitch if adjustable. | 2. | Increase pitch / consult factory | |
Unbalanced current | 1. | Unbalanced line voltage due to: | 1. | Consult power company and/or | |
(5% from average) |
| A. | Power supply. |
| electrician. |
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| B. | Unbalance system loading. |
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| C. | High resistance connection. |
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| D. | Undersized supply lines. | 2. | Replace motor. |
| 2. | Defective Motor. | |||
Excessive voltage drop | 1. | Inadequate power supply. | 1. | Consult power company. | |
(2 or 3% of supply voltage) | 2. | Undersized supply lines. | 2. | Increase line sizes. | |
| 3. | High resistance connections. | 3. | Check motor leads and other | |
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| connections. |
Overload relays tripping | 1. | Overload. | 1. | Reduce load on motor or increase | |
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| motor size. |
| 2. | Unbalanced input current. | 2. | Balance supply voltage. | |
| 3. | Single phasing. | 3. | Eliminate. | |
| 4. | Excessive voltage drop. | 4. | Eliminate (see above). | |
| 5. | Frequent starting or intermittent | 5. | Reduce frequency of starting and | |
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| overloading. |
| overloading or increase motor size. | |
| 6. | High ambient starter temperature. | 6. | Reduce ambient temperature. | |
| 7. | Wrong size relays. | 7. | Correct size per nameplate current | |
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| and service factor. |
| 8. | Improper overload settings of | 8. | Readjust to motor FL Amps x S.F. | |
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| adjustable relays. |
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Motor runs very hot | 1. | Overloaded. | 1. | Reduce overload. | |
| 2. | Blocked ventilation. | 2. | Fouled fill or air restriction. | |
| 3. | High ambient temperature. | 3. | Reduce ambient temperature. | |
| 4. | Unbalanced input current. | 4. | Balanced supply voltage. | |
| 5. | Single phased. | 5. | Eliminate. | |
Motor will not start | 1. | Single phased. | 1. | Shut power off – eliminate. | |
| 2. | Rotor or bearings locked. | 2. | Shut power off – check shaft | |
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| rotation. |
Excessive vibration (Mechanical) | Out of balance | 1. | Check to be sure motor mounting | ||
| 1. | Motor mounting. | |||
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| hardware is tight. |
| 2. | Motor. | 2. | Replace motor. | |
Note: Consult Warranty page prior to replacing or repairing any cooling tower components. Delta recommendation and consent to remedy material and workmanship defects is necessary, to avoid breach of Warranty.
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