Archive for category: Fan Facts
Americraft offers several powder coating finishes that can be applied to industrial fans and ventilation products depending upon the environment in which the fan will operate. Prior to applying our powder coat finishes, the fan housings are washed with an iron phosphate detergent that improves adhesion and corrosion properties of the paint coating.
Our standard “Americraft Gray” is a Super Durable Polyester TGIC power coating that offers superior outdoor weathering compared to standard polyesters. This powder coating is used on the vast majority of our products. The Super Durable Polyester enhances the durability and performance on interior and exterior metal surfaces. Key applications are as follows:
- Suitable in decorative applications where product will be exposed to sunlight (UV stabilizer)
- Applied to agriculture & construction equipment
- Applied to architectural metal products fabrications & extrusions
- Applied to recreation equipment, automotive trim, truck bodies, lawn & garden equipment and related products.
In addition to the standard “Americraft Gray”, Americraft offers an Epoxy powder coating and a Zinc Rich Primer powder coating. For more severe environments, Americraft offers a hot dipped galvanized coating.
Epoxy (Interpon 100)
Interpon 100 is an epoxy based powder coating that exhibits excellent corrosion protection and chemical resistance. The epoxy is applied as a base coat and top coated with the Americraft Gray Super Durable Polyester TGIC. The epoxy base/top coat combination is well suited for environments in which caustic substances are present.
Zinc Rich Primer
Zinc Rich Primer is an epoxy that offers superior mechanical properties and chemical resistance. For added corrosion protection, we apply the zinc rich primer as a base coat to the Americraft Gray Super Durable Polyester TGIC coating. The primer/top coat combination is used primarily on roof exhausters and any fan that will be exposed to outside elements.
Hot Dipped Galvanized Finish
Excellent “exterior” coating that provides total protection across the entire surface of the fan housing as a result of the “dipping” process. The galvanizing, zinc and iron interact and form intermetallic layers, which are harder than steel. Hot dipped galvanized finish can be painted or powder coated which adds another layer of protection. This finish will provide decades of excellent protection in harsh, exterior environments. Key characteristics are as follows:
- Excellent abrasion resistance
- Cathodic protection stops rust corrosion from spreading if surface is scratched
- The finish will appear chalky over time, but does not affect performance
- Highly desirable in salty air environments
- Can be washed down easily
Contact us at Americraft if you would like to discuss your specific fan application and we will help you select the best finish to meet your needs.
A pressure blower is a centrifugal fan designed such that the air enters the fan inlet, is forced around the inside of the housing, and exits at a 90 degree angle from how it entered the fan. Most pressure blowers have a straight blade radial wheel, but some are available with a backward curved or shrouded wheel, depending on the application. Americraft pressure blower wheels are cast aluminum, and with the exception of a couple of sizes, are straight radial wheels. This means that the blades are at a 90 degree angle to the backplate of the wheel.
Pressure blowers are used when the application requires a small to medium amount of CFM at higher static pressures than an axial fan is capable of producing, up to 11-12” S.P. water gage for our blowers. Pressure blowers consume horsepower the opposite of axial fans as the higher the static pressure, the less horsepower is consumed by a blower.
How to Select the Right Pressure Blower
The proper selection of a pressure blower is dependent on the same criteria as an axial fan as you need to know the CFM, system static pressure, operating environment inside and outside of the blower which includes temperature, elevation, and ambient noise level.
What Are Pressure Blowers Used For?
Some of the many applications for our cast aluminum blowers include: weld smoke removal, mounting on the top of dust collectors, non-abrasive material conveying, vehicle exhaust removal in garages and fire departments, air source for air knives, and combustion air for gas burners.
Finally, our pressure blowers have cast aluminum wheels and housings which are naturally non-sparking and are suitable for use in applications requiring AMCA type “B” spark resistant construction.
Unfortunately, there may come a time when a fan propeller is damaged during operation. It could break due to a foreign object striking it or possibly a build up from paint, dust or some other residue resulting from the environment in which the fan operates. Murphy’s Law says it will happen at a critical time and production comes to a grinding halt. Time is of the essence and you need to get the fan back in operation as soon as possible.
Propeller Selection Information
Before you contact Americraft, check out the list below and try to answer as many questions as possible. The first five are very important for selecting the optimal propeller that will best deliver the optimal airflow of the original propeller. However, the remaining five are also important in helping us fine-tune the selection, but we can help you determine these requirements as we work through the details of the TOP 5.
We’ve left you spaces on each item if you’f like to download and print a copy to work through.
Top 5 – “Ideal to Know”
#1 ___________Size/Trim Diameter
The proper way to measure the diameter of the propeller is tip to tip. Don’t assume the diameter based on the size of the fan. For example, the propeller on an Americraft 36” tube axial fan measures 35 ¼” tip to tip.
#2 ___________Propeller RPM
If you don’t know the RPM of the propeller, for a belt driven application, provide the pulley sizes and the motor RPM. For direct driven fans, the fan speed is equal to the motor RPM.
#3 ___________Bore Size
The proper way to determine bore size for a belt driven fan is to measure the diameter of the fan shaft. For direct drive applications, reference the motor frame size.
#4 ___________CFM Requirements
This information is ideal in designing a propeller that will deliver the optimal air requirements. If CFM is not known, we will design the propeller to deliver the optimal CFM that the motor HP can deliver without overloading the motor.
#5 ___________Static Pressure Requirements
This information is also important to know when designing a propeller that will deliver optimal CFM without overloading the motor. Let us know if the fan is operating with ductwork attached or any other restrictions that would affect CFM.
5 “Nice to Know”
#6 ___________Bore Type (straight, trantorque, or taperlock)
#7 ___________BHP Requirements
#8 ___________Hub Location (air entering or air exiting)
#9 ___________Construction Material (e.g. carbon steel, stainless, cast aluminum)
#10 ___________Operating Temperature
Ready to contact Americraft to replace your fan propeller? Fill out our online form or give us a call Toll Free at 800-848-2938 or locally at 513-489-1047.
Using Variable Frequency Drives (VFD’s) for Industrial Ventilating and Exhaust Fans
The Americraft sales team frequently receives inquiries from customers wanting to purchase a variable frequency drive (VFD’s) for a fan application. Once we have a better understanding of air requirements and the environment in which the fan will operate, we will work with the motor manufacturer to identify the correct motor and VFD that will allow the fan to run efficiently.
I did some research to identify the most relevant information about motors and VFD’s for use in fan applications. This information is not intended to be technical by any means, but more to provide general information to help our customers think through the design process and consider all aspects of the environment in which the fan will operate.
65% of Industrial Electrical Energy is consumed by the electric motor.
An interesting statistic worth sharing is the fact that more than 65% of industrial electrical energy consumed is a result of the electric motors. Governments around the world are encouraging the more effective use of motors with variable speed drives. In the past, VFD’s were not a top choice because they were expensive and cumbersome in terms of size. It could take years to realize a decent return on investment. More common are the use of dampers, inlet vanes and two-speed motors to control air flow in ventilation systems, but they are not all energy efficient.
Fortunately today, advances in technology have driven down the cost and size of VDF’s, thereby realizing a return on investment in a matter of months in most cases.
Basic Questions You Need to Answer Before Purchasing a VFD
If you are interested in controlling air flow and boosting energy efficiency, contact us and we will help you select the best fan, motor and VFD to meet your needs. Before you make the call, here are some basic questions you should be able to answer with regard to the motor, electrical system and environment in which the fan will operate:
|Motor Requirements:||Electrical System:||Environment:|
|Motor Voltage||Voltage||Dripping Water?|
|HP or kW||Frequency||Oil?|
|Motor Rated FLA (amps)||Phase||Airborne dust?|
|Distance between drive and motor (feet)||Wash-down?|
Motors Operating on Variable Frequency Drives (VFD’s)
Today, most standard NEMA Premium Efficiency motors are designed with characteristics that enable use with VFD’s on variable torque loads such as the majority of fan applications. These motors will be labeled as either “Inverter Ready” or “Inverter Rated”, depending upon the motor manufacturer.
There are motors rated as “Inverter Duty”, which are designed specifically for use with VFD’s and have all of the characteristics of premium efficiency motors along with larger frames or external blowers to cool the motor regardless of its speed. There may be situations where an “inverter duty” motor is desired for a fan application, but it’s usually not required.
Single Phase Motors and VFD’s
We get a lot of questions from customers wanting to use a single phase motor with a VFD. This is not possible because of the starting mechanism used in most single phase capacitor start motors. The starting mechanism is not built to withstand changes in speed and will fail.
VFD’s convert Single Phase Input to 3-Phase Output
It’s important to understand the voltage requirements in which the motor and VFD will operate. For example, if your facility has 115V, single phase electric, most VFD’s will operate a 3-phase motor up to 1 ½ HP. If your facility has 230V, single phase electric, most VFD’s will operate a 3-phase motor up to 3HP. Higher horsepower motors are also a possibility, depending upon the application and the VFD used.
Contact us and we will work with the motor/VFD manufacturer to size the motor and VFD appropriately to meet your voltage requirements.
Fan noise is oftentimes overlooked when choosing a fan. Fan noise will vary by fan type, flow rate, pressure and fan efficiency. Other factors such as walls, floors, ceilings and other equipment will have an effect on noise reflection and absorption to varying degrees as well. Here are a few tips you will want to consider and understand before selecting a fan:
OSHA Exposure Limit
From a safety standpoint, OSHA’s (Occupational Safety & Health Administration) permissible exposure limit is 90 dBA based on a time-weighted average over an 8-hour day. Similarly, NIOSH (National Institute for Occupational Safety & Health) recommends limiting the 8-hour exposure to less than 85 dBA. It’s also important to know that decibels are measured on a logarithmic scale, which means that a small change in the # of decibels will result in a huge change in the amount of noise and potential damage to a person’s ear. For example, a thunderclap measured at 120 dBA can be over 30 times as loud as the noise at 70 dBA.
Understanding Decibel Levels
The ear is a sound pressure receptor. To get a feeling for decibels, look at the table below which gives values for the sound pressure levels of common sounds in our environment. When making noise comparisons, keep in mind that noise measured at 120 dBA for an extended period of time can cause pain or possible hearing loss.
|Outdoor/Indoor Noise||Sound Pressure Decibel Level (dBA)|
|Jet aircraft at 50 ft. away||140|
|Threshold of pain||130|
|Threshold of discomfort||120|
|Chainsaw at 3 ft.||110|
|Disco at 3 ft. from speaker||100|
|Gas lawn mower at 3 ft.||90|
|Diesel truck at 50 ft. at 50 mph||80|
|Vacuum Cleaner at 10 ft.||75|
|Normal Speech at 3 ft.||70|
|Heavy traffic at 300 ft.||65|
|Large Business Office||55 *|
* Americraft industrial fans are NOT well suited for an office environment.
The Americraft fan dBA levels can range anywhere from the low 70’s to high 90’s at 10 ft. If noise is an issue, consider using a larger fan at a lower speed (rpm) or a belt-driven fan. Feel free to contact our office if you have any questions about a specific model. We would be happy to help you in all aspects of your air moving requirements.