Lumber Dry Kiln Duty Motor Repair

Lumber Dry Kiln Motor Repair Shop

As an electric motor repair shop that has been in operation since 1946 and which also specializes in the manufacturing of high temperature kiln motors, EBI became a reference in the industry for the repair of such electric motors. Since EBI's primary customers come from the sawmill industry, we developped knowledge and repair methods that answer the needs of the lumber industry that uses high temperature motors in lumber kilns. Thanks to our expertise in repairing kiln motors from our very beginnings, we were eventually able to manufacture ourselves our own brand of kiln motors: the EBI Dry Kiln Duty Motors.

Ensure that lumber kiln motor fans are balanced  Each lumber kiln motor fan must be properly balanced    

1 year of Warranty on High Temperature Kiln Motor Repairs

Thanks to our long term collaboration with the sawmill industry and thanks to our expertise in kiln motor repair, EBI offers one year of warranty on each repaired kiln motor. Each of our kiln motor repair activity is strictly quality controlled according to our ISO 9001:2015 certification. EBI is also a long-term member of EASA (Electrical Apparatus Service Association), an association of collaborators who ensure that we stay up to date with the latest kiln motor repair practices with the most top notch repair equipment. At EBI, our kiln motor repair procedures are followed according to the highest recommended quality standards of EASA. EBI is also a member of the EASA Quebec Chapter to make sure that we are aware of local needs and regulations in the field of lumber kiln motor repair. 

Kiln motor repair by EBI Electric  IEC kiln motor repair : replacement of terminals by EBI Electric  Kiln motor repair at EBI Electric

Inspection of Kiln Motor and Diagnosis

Once the end bells of the kiln motor are removed, a visual inspection allows us to assess the quality of the winding at a glance. We are then able to see if the winding is burned or if the lubrication of the bearings was done according to the manufacturer's recommendations. In some cases the winding of the kiln motor could be tested with a Hipot test in order to see if there are ground faults, open circuits, short circuits or inadequate electrical connections.  

Kiln motor winding that needs to be replaced   Kiln motor burned windings

The Three Most Common Causes of Dry Kiln Motor Failures

Some of the causes of lumber kiln motor failures are more common than others. We simply have to learn about them in order to maximise the lifespan of high temperature kiln motors. 

Cause of Kiln Motor Failure 1: Inadequate Kiln Motor Stator Frame Leading to Winding Contamination

It is important to choose an electric motor specially designed for the ventilation process in lumber drying. Some electric motors with an ODP frame (Open Drip Proof) are sometimes wrongly used in a lumber dry kiln to control a kiln fan. That type of frame has openings through which we can directly see the winding of the motor and its insulation components. The use of such type of motor is not recommended in a dry kiln since moisture (water droplets), acidic air, dust and sawdust particules and high heat will directly affect the winding of the kiln motor and eventually lead to short circuits. 
ODP kiln motor inadequate for lumber drying  ODP motor polluted by environmental contaminants through openings

Choose a TEAO Kiln Motor Frame

As highlighed by The Snell Group that specializes in the evaluation of electric motors,  

"Open Drip Proof (ODP) motors are usually much cheaper than TEAO motors, but are highly susceptible to whatever contaminants are present in the ambient environment. Anything and everything in the air surrounding the motor is pulled through and around the interior of the motor. When we add some humidity to the mix it means a hot motor in the process of cooling off is not only pulling in air, it’s pulling in moisture too. This condensation coupled with dust and particulate from the manufacturing process attaches to the insulation. This in turn can make the motor run hotter than it should. [. . .] To put it bluntly, installing an ODP motor outside, or inside in a moderately dirty environment is a substantial waste of money. [. . .] These motors last a fraction of the time that a TEAO motor does." (The Snell Group : The Importance of Motor Enclosure Type)

Because of the presence of humidity, the acidity released by lumber in the process of drying, sawdust, intense heat, condensation effect and all the other pollutants transported in the air of a lumber dry kiln, it is recommended to use a TEAO type of motor to propel the fans in a lumber kiln. As shown by the following images, the ambient environment of a lumber dry kiln contains many contaminants and one must ensure that the frame of kiln motors (the stator) is completely closed to avoid any contamination. 

Kiln motor repair warrantied 1 year by EBI Electric  Kiln motor repaired by EBI Electric and reinstalled

When an electric motor runs in a lumber dry kiln, its winding must not be exposed to the ambiant air and environment. In order to avoid that situation, it is preferable to use a TEAO motor (Totally Enclosed Air Over) in order to maximise the lifespan and efficiency of the kiln motor. At EBI, when we repair a dry kiln duty motor, our repair equipment such as our motor Core Loss Tester allows us to assess the density of the stator cast iron and to validate if it is still optimal for the dissipation of heating for a motor dry kiln ventilation application. 

TEAO kiln motor repaired by EBI Electric  Kiln motor repaired by EBI Electric and warrantied 1 year

Cause of Kiln Motor Failure 2: Inadequate Kiln Motor Bearing Lubrication 

The lubrication of lumber kiln motor bearings is crucial. Make sure that you have read the maintenance instructions of the kiln motors that you use. Normally the manufacturer's lubrication procedure shoould include three important indications: 

I-The frequency of lubrication according to a certain number of hours of use

II-The quantity of lubricant (grease) in grams that needs to be injected according to the type of bearings used and the frequency of lubrication

III-The type of lubricant required : there are different chemical ingredients at the base of every lubricant and those ingredients are not always compatible with one another

Kiln motor bearings blocked by an excess of grease  Dried kiln motor bearings due to lack of grease  Ball bearings of kiln motor that need to be replaced  

During the lubrication of your TEAO dry kiln duty motors, make sure that the grease fittings are clean and that the drain plugs underneath each motor end bells are removed to allow the old lubricant to be replaced as suggested by the following image.

The different types of kiln motor grease or lubricants cannot all be mixed. As mentionned before, the chemical base is different from one lubricant to another. Moreoever, the grease used for class F electric motors (standard application) can be different from the grease used for high temperature class H motors used in lumber dry kiln ventilation applications. For example, the lubricant used by EBI in the manufacturing process of the EBI Dry Kiln Duty Motor (the SIN EP2 grease) is based with a calcium sulfonate complex which is not compatible with other lubricants based with aluminum, argile, polyurea or sodium for instance. On the other hand, a grease based with a calcium sulfonate complex is compatible with a lithium or calcium grease. When it is time for the maintenance of the bearings of a lumber kiln motor, the grease or lubricant recommended by the manufacturer must be the same or it must be compatible with the one you use for your other electric motor maintenance. Consult the EBI Dry Kiln Duty Motor lubrication procedure by clicking this link.

Cause of Kiln Motor Failure 3: Unbalanced Fan Affecting Bearings and Rotor

A lumber dry kiln duty motor is manufactured to propel a fan that circulates ambiant air in one way or another in a lumber dry kiln. This fan must be balanced at low tolerances. For example, the ISO 14694 article concerning indusrial fans specifies the quality and the tolerance required for the balancing of a fan. This fan category is BV-3 and for such equipment classification, the balancing tolerance of a new fan must be under G6,3 to respect the ISO regulation. When an electric motor fan is unbalanced, it creates vibrations that cause pressure and a crank shaft effect on the rotor of the motor or more specifically on the bearings stabilizing the rotor. Such situation creates friction leading to motor parts heating and damage which eventually cause kiln motor mechanical and electrical failures. Make sure that the kiln motor fans are properly balanced at the lowest possible tolerance and if need be, ask for the services of dynamic balancing specialists.

New rotor for kiln motor by EBI Electric Damaged kiln motor rotor due to crank shaft effect caused by unbalanded fan
Kiln motor fans must be balanced at all times to preserve the quality of the lumber kiln motor

Dry Kiln Duty Motor Repair Steps

A dry kiln duty motor is basically a high temperature electric motor which manufacturing is optimised for lumber drying. All the mechanical parts of this motor and the way it will be winded must prepare it to face the most extreme high temperature environment with high humidity, acidity with a mix of different air contaminants. At EBI Electric, when we repair a kiln motor, no step is neglected and the motor goes through a complete refurbishement process in the finest details. That allows EBI to offer a kiln motor warranty repair of 1 year. Here are some of the 35 steps in the process of lumber kiln motors at EBI Electric: 

1-Motor cleaning and baking in one of our ovens

Kiln motors entering oven for baking during repair process   The defective winding of kiln motors must be removed during the repair procedure

2-Winding extraction with specialized equipment and winding extractor

3-Corrosion, humidity and acidity treatment for optimal motor protection (note that there is significant acidity emitted by the drying of lumber and some wood species are more acidic than others)

4-Lap rewinding by hand for optimal heat dissipation inside the stator  

Remplacement of lumber kiln motor winding by EBI Electric  Dry kiln motor repair and rewinding process  Repaired dry kiln motor reassembling by EBI Electric

5-Replacement of bearings by optimised C3 bearings ideal for a high temperature lumber drying ventilation application. At EBI, we offer the sealed bearing or the regeasable bearing option to our kiln motor customers. 

Companies that Trust EBI with the Repair of Wood Kiln Motors

Many companies in the business of wood transformation and manufacturing trust EBI for the repair of their kiln duty motors. Some of those companies are sawmills, wood flooring and furniture manufacturers. Many of them are from the United States or outside the state of Quebec and send us their kiln motors for evaluation and repair by palet every year. Thank you for trusting us with the repair of your dry kiln duty motor

2250, 90e Rue
Saint-Georges (Quebec), G5Y 7J7, Canada

Contact us:


Business Hours
Monday to Thursday: 8 a.m. to 5 p.m
Friday: 8 a.m. to noon


1 418 228-5505

Toll Free:
1 888 228-5505

1 418 228-5630


2023 © EBI Electric All rights reserved