Motors
A cooling tower fan motor spends its life in saturated, chemically treated air, and it is switched far more often than a process motor. Ordinary TEFC motors do not last there.
Understanding the component
Cooling tower motors are specified as severe duty or cooling tower duty rather than general purpose. The differences are in the details that resist moisture: sealed bearings and shaft seals, drain provisions, corrosion-resistant hardware, and epoxy coating on the windings and frame, double-dipped epoxy where the environment justifies it.
Motors are available in essentially any horsepower rating. Common frame sizes run from 143 through 449, with special frames available. Typical construction is Class F insulation with a 1.15 service factor and Class B temperature rise, most commonly three-phase, 60 Hz at 460 volts, with other voltages available.
Two-speed motors remain common on cooling towers because they are a simple way to reduce fan power in cool weather and to run at half speed for de-icing. Variable frequency drives do this better and also reduce starting stress on the driveline, but they require a motor rated for inverter duty.
We supply components for cooling towers from every manufacturer, including towers whose original makers no longer exist. If it is on your tower, we can identify it.
What actually goes wrong
These are the failures we find in the field, roughly in order of how often we find them. If you recognize one, we can usually tell you what to check next over the phone.
| Failure | What it means |
|---|---|
| Winding failure from moisture | The characteristic cooling tower motor death. Almost always a motor that was not specified for the environment, or whose coating has been breached. |
| Bearing failure | Accelerated by moisture ingress, by driveline misalignment pulling on the shaft, and by frequent starting. |
| Corroded conduit and terminal box | Water tracks into the terminal box and the motor fails electrically while the motor itself is fine. |
| Repeated starting damage | Cooling tower fans have high inertia. Frequent starts stress windings, couplings and gearboxes alike; a two-speed motor or a VFD reduces the problem substantially. |
Manufacturers and product lines
We are independent, so the recommendation follows your tower, your water and your duty rather than a single manufacturer's catalog.
Siemens
Including the Medallion and EPACT premium-efficiency ranges.
TECO-Westinghouse
Successor to the Westinghouse TEAMPlus and MAX-E1 motors found on many existing towers.
Baldor / ABB
Severe duty and cooling tower duty ranges.
US Motors / Nidec
Cooling tower duty and inverter-duty ranges.
Other major manufacturers
Specified to match your existing frame, mounting and starter arrangement.
Names you may find on the nameplate
Including lines that are no longer current. Many of the towers we work on are thirty to fifty years old, and identifying the modern equivalent of a discontinued component is part of the job rather than an obstacle to it.
- Siemens Medallion
- Siemens EPACT
- Westinghouse TEAMPlus
- Westinghouse MAX-E1
- Reliance Electric
- GE KS
- Baldor
- US Motors
What we would tell you on the phone
Some of those older names no longer exist.
Reliance Electric, GE's KS line and the original Westinghouse motor business have all been absorbed or discontinued. They are listed above because they are still on nameplates. Identifying the current equivalent for a discontinued motor is routine work for us.
Specify for the environment, not the horsepower.
The horsepower is the easy part. Whether the motor survives depends on the enclosure, the coating, the bearing arrangement and the hardware, which is where a general-purpose motor bought on price fails.
Check the driveline at the same time.
A motor that failed on bearings may have been killed by a misaligned driveline. Replacing only the motor means replacing it again.
Usually replaced or inspected at the same time
Gear reducers
Right-angle fan drives, including direct replacements for the Marley Geareducer line. Frequently rebuilt in place.
View componentDrive shafts & couplings
Composite and steel drive shafts with flexible disc couplings: Addax, Amarillo, Rexnord Thomas and TB Wood's.
View componentVibration switches
Mechanical and electronic vibration cut-outs: Murphy VS2, PMC/BETA and Metrix. The cheapest protection a fan drive can have.
View componentFans
Fiberglass and aluminum fan assemblies, blades and hubs: Hudson, Amarillo Chittom, Moore and Cofimco.
View componentSend us the nameplate and we will identify it
The fastest route to a correct quote is a photograph of the nameplate and of the component in place. Model numbers get superseded and drawings go missing; photographs do not lie.
- Phone
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- Shop & office
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3811 Cedar Blvd Ste A
Baytown, TX 77523