Before we dive into ODP vs TEFC motor, we need first to know more about each type. But for a quick comparison between ODP and TEFC, I will list the differences in the table below.
ODP vs TEFC Motor Table
What Does ODP Motor Stand for?
ODP “Open Drip Proof” where the motor chamber has open vents, so air can flow directly over the winding and cool it down.
No fans are needed in this type of motor. ODP design is suitable for motors that run cooler and don’t overheat.
When electrical current flows through the windings of an electric motor it produces heat while operating. Due to this heat, the motor temperature rises, This rise in temperature could cause the motor to be burnt. Several motor cooling methods are used to reduce this temperature rise.
The disadvantage of ODP Motors
In ODP motors the protection against dust and humidity is poor, So the dust and humidity can directly enter the motor, making a kind of dirty winding and bearing.
Some motor manufacturers make laminated winding and sealed bearings to overcome dust and airborne contaminants issues.
Can I use ODP outdoors?
So, from the above, it’s clear that ODP motors are sufficient for indoor industrial applications only.
If you use an ODP motor outdoors moisture and dirt will cause motor overheating, rapid corrosion, and failure. This failure may be a temperature rise due to bad cooling efficiency, and sometimes it may be a short circuit inside the motor.
In my work, I face many damaged electric motors and generators due to dirt and moisture. I work in a desert. In winter we face sandy storms, moisture, and heavy rains.
If a motor or a generator, for any reason, has openings, like the ODP motors, the fine sand enters into the windings and accumulates on them. Moisture and sand cause a short circuit between the winding. The result is a completely damaged motor or generator.
This is why we should pay great attention to the motor IP and work environment.
I have written a detailed article about motor burn out reasons, you can find it here.
ODP motor applications
ODP motors are suitable for all indoor applications. You can find open drip-proof motors in the following applications:
- Indoor electric transformer cooling fans.
- Home apparatuses, such as washing machines and air fans.
- Air compressors for indoor use only.
- Water treatment facilities.
- All indoor industrial applications where the working environment is dry and clean.
The open drip-proof enclosure is vented at its back end to allow cooling air to enter the winding. So, the open drip-proof motor applications should be in wet clean locations.
What is the ODP motor IP rating?
Most ODP motors are designed with IP23. This IP rating is of course for indoors.
Digit 2 means the motor is well protected against 12mm solid parts and human fingers. While the second IP digit, 3, means the motor is protected against water drops falling up to 60 degrees from the vertical.
For more details read my article IP ratings, here.
Can Open Drip-proof (ODP) motors be used in industrial areas?
Open drip-proof motors aren’t very reliable to operate in the industrial sector. The IP of most ODP motors is IP23 meaning that these motors can withstand an environment of drops falling up to 60 degrees from the vertical.
Open-drip-proof motors are unacceptable for applications with the potential for splashes, washdowns, or flammable gases or debris, which exist in almost all industrial applications.
Industrial Sector is a place where cleanliness is not the top priority. However, if the industry is related to the production of products that demand cleanliness around them, cleanliness is assured only in the place where the product is stored, and packed.
The ambient of the open drip-proof motors must be clean so that no dust or fluids of hazardous kind enter the motor. They are optimal for clean, indoor uses.
Example of Open Drip-Proof motors?
The home appliances have ODP motors, such as:
- Compressor to be used inside the house.
- Ceiling fans.
- Washing Machines.
- Air coolers use Open Drip-proof Motors.
As the ambiance of home appliances is far better than that of industrial equipment, Open-Drip Motors are reliable.
The lightweight, as well as the economic factors, are also better for the Open Drip motors than other motors when used inside the home.
Also, in some industrial areas where the environment is clean and dry, open drip-proof motors are used. If the motor is closed and drip-proofed, it can be even used for the water pumps.
Why do Open Drip-proof motors fail?
The most common reason that makes Open drip-proof motors fail is that, their poor protection against dust and humidity.
As obvious from its name i.e., open drip, it is open to airflow and also does not have any cooling fan. So, anything can enter the motor and windings. It reduces motor efficiency.
Dust clogs in the motor windings. If it is placed outside, rainwater shorts the windings which may result in a fatal accident, or a short circuit.
do drip-Proof motors cost more than regular motors?
Drip-proof motors do not cost more than any regular motor.
Drip-Proof motors are inexpensive and readily available. The first cost of a drip-proof motor is lesser than other motors.
But if the motor is being used in an exposed environment, the dust and water cause faults in the circuitry that leads to either getting the motor repaired or installing a new one.
So, the maintenance cost of open drip motors is more than the maintenance cost of a regular motor if set in an unsuitable environment.
Are drip-proof motors more efficient than regular motors?
Open Drip motors are more efficient than regular motors. When placed in a dry condition and the ambiance is clean, open drip motors work perfectly.
As the motor has a proper airflow passage through itself, it does not overheat. Overheating decreases the efficiency of the system. The open drip motor does not overheat and works efficiently.
You can read my detailed article about, Electric motors temperature rise, causes and solutions.
What does TEFC motor mean?
Totally enclosed fan-cooled motor also represented as TEFC, is a motor with its chamber closed off, which requires an external fan to cool it down.
Cooling a motor of this type requires fans to drive air on the motor body.
As one of the main disadvantages of ODP motors is that they are not sufficient for the outdoors. TEFC motors are the solution to this issue.
The completely enclosed TEFC motor is well protected from the outside environment, dust, rain, and humidity.
TEFC motor and working outdoors
The opposite to ODP motors, the TEFC motors are sufficient for outdoor or wet location applications.
The enclosure prevents air from outside to enter the motor. In this type of motors, a fan blows outside air to cool the motor through its outside body.
This type of motor is well designed to work outsides because the enclosed body of a totally enclosed fan-cooled electrical motor doesn’t allow any air exchange between the inside and outside.
Can TEFC motors be used in hazardous locations?
Not all TEFC motors are labeled as EX motors for hazardous areas use. It must be stated on the motor nameplate clearly the EX classification of the motor to be used in hazardous locations.
TEFC doesn’t tell us anything about the motor EX protection degree. It’s just the cooling method of the motor.
We are talking about two different terms. i.e cooling method of the motor and the explosion-proof degree.
The point is, you should ensure the motor EX protection degree and check the hazardous area classification.
Which motor type is better ODP or TEFC?
Depending on the application and location of the motor you can choose the best one for you.
If your location is outdoors or wet, then a TEFC motor will be the best choice. While the ODP motor is suitable only for indoor applications.
You should choose the motor type carefully. If you choose the wrong motor you may charge your organization more money.
If you choose ODP for wet locations, it may get damaged. And in the case of choosing a TEFC motor for indoor dry location, it may be more expensive than ODP one.
Why do electrical motors need cooling?
Motors like all other electric devices and equipment need temperature rise control because the temperature rise causes the winding insulation to get damaged and then a short circuit may happen and cause complete motor damage.
So we need to cool the motor down, This is where several methods of cooling are used.
Electrical motors produce heat while operating. This heat is a result of current passing through windings, friction, losses, and ambient temperature.
This heat causes the motor temperature to rise. If this rise keeps up it will cause the motor winding insulation to decrease and then to electrical short-circuited and burn out.
So, one of the most important things we consider when choosing a motor is the location temperature, and the motor insulation class.
As I told you, I work in the desert, this is why we choose motors with an ambient temperature ranges of 5°C mini and 55°C max. And insulation class of F.
For more details about motor insulation class read my other article here.
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