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Motor Modification

Motor Modification

Sometimes your motor may require accessories because of aspects like environment, load and stray voltage. If you find yourself in this situation, look to L&S Electric to provide you with expert motor modifications.

Through conduit box repositioning, lead extension, flange kit installation, shaft grounding or the incorporation of space heaters, you can optimize the functionality of your equipment and extend its life.

Motor Modification

Conduit Box Position

The conduit box is usually on the side of the motor where the stator (windings) leads are attached to leads going to the power supply. The normal position for NEMA "F1" motors is located on the left side when facing the drive end of the motor. The normal position for IEC "B3" motors is located on the right side when facing the drive end of the motor. For convenience, the conduit box can be repositioned for easy access.

Extended Leads

Medium and large motors are usually provided with leads extending from the winding to the terminal box. If the leads are not long enough, extended leads are provided.

Flange Kit Installation

There may be a situation where it’s not possible to install an electric motor to the equipment that it’s intended to operate. Flange kits provide the correct conversion to precisely mount the motor for proper operation.
Resistance Temperature Detectors (RTDs)

RTDs are sensors used to measure temperature by comparing the resistance of an RTD element with temperature. RTD elements are made up of a length of fine, coiled wire wrapped around either a glass or ceramic core and placed inside a probe for protection.

Various RTD Materials:

  • Platinum
  • Nickel
  • Copper
  • Balco
  • Tungsten

RTDs are among the most precise temperature sensors. Theyíre protected from electrical noise which makes them ideal for measuring temperature in several industrial environments, especially motors, generators, and other high voltage equipment.

Shaft Grounding

Variable frequency drives deliver great benefits with respect to energy savings and extending equipment life. However, variations in frequency may create electrical discharges. This electrical discharge looks for a path to ground, usually through the bearings, which wreaks havoc on the bearings in your rotating equipment. Over time, this bearing damage may cause motor failure.
A proven method to prevent electrical discharges from damaging bearings is the use of shaft grounding rings. Carbon fibers in the grounding rings provide a safe path for the electrical discharges to go to ground.

Other methods to protect the motor from electrical currents include insulated bearings, or an insulated hub end shield in the non-drive end.

Space Heaters

Space heaters eliminate condensation problems in motors by maintaining a winding temperature 41 ºF to 50 ºF above the surrounding air temperature. Two situations where space heaters are recommended are:

  • Motors operating in environments with a relative air humidity up to 95% where the motor may idle for 24 hours or longer;
  • Motors operating in environments with relative air humidity more than 95%, regardless of how often the motor runs. 

If there isn’t enough clearance for rigid strip heaters, the solution may be flexible heaters. These heaters can be connected to the outside diameter of the end turns of varnished windings. If the motor is large, heaters may have to be installed on both ends.