110V Portable Explosion-Proof Fan for High-Pressure Ducting

Designing a 110V Portable Explosion-Proof Fan

The customer needed a portable explosion-proof fan for tight spaces. First, the job required strict safety compliance. The site had hazardous gases. Therefore, the fan needed an ExdIIBT4 rating.

This rating covers T1 to T4 temperature zones. Meanwhile, these zones exist in chemical plants and shipyards. However, the main problem was the power supply. Therefore, standard industrial blowers use 220V or 380V.

Instead, the customer asked for 110V 60Hz power. In practice, they also wanted a standard US plug. The order was for more than 1000 units. So, we could not just add a simple adapter.

We had to build 110V motors directly. Meanwhile, furthermore, the design faced tough airflow limits. The blowers had to push air through long PVC hoses. Therefore, the LWA-300UM needed a 10-meter hose.

Meanwhile, the smaller models used 5-meter hoses. In practice, long hoses create a lot of drag. Consequently, the fan had to push past high pressure. As a result, a standard axial blade would fail here.

Next, we reviewed the exact safety rules. Meanwhile, the fan must meet Class I standards. It also must meet Class II standards. Finally, any motor sparking must stay inside the shell.

The outer surface must stay cool. Therefore, a hot surface can ignite gas in the air. The ExdIIBT4 mark proves the unit stays safe.

Choosing the Right Motor and Impeller

First, we looked at standard 220V LWA models. In practice, we thought about using external step-up transformers. However, we rejected that idea quickly. As a result, a transformer adds extra weight and size.

It ruins the portable design of the housing. Moreover, furthermore, a basic transformer lacks the ExdIIBT4 safety rating. Adding one would break the explosion-proof rules. Instead, we chose to redesign the internal motor.

We built new stators for 110V 60Hz power. Consequently, dropping the voltage from 220V to 110V changes things. The LWA-300UM model needs 370W of mechanical shaft power. Meanwhile, to get 370W at 110V, the current must double.

So, the motor needs much thicker copper wire. Therefore, thicker wire prevents the motor from getting too hot.

Upgrading the Portable Explosion-Proof Fan Blade

Next, we had to fit this thick wire. In practice, the stator slots have very limited space. We changed the winding pattern to fit the copper. As a result, we strictly kept the explosion-proof safety gaps.

Meanwhile, we fixed the heavy static pressure problem. Moreover, the PVC hose causes huge air drag. Airflow stops if a normal blade faces this drag. Therefore, we used a pitched aluminum impeller.

The 300mm model generates 500 Pa of static pressure. In short, it spins at a fast 2800 RPM. Finally, we must note the cost of this choice. Meanwhile, a custom 110V stator adds days to our schedule.

It takes longer than shipping standard 220V fans. Even so, the final portable explosion-proof fan delivers 3720 m3/h of air. It successfully pushes air through the whole hose.

Technical Specifications

First, look at the static pressure limits above. Therefore, these numbers show the maximum duct drag allowed. In short, the 300UM unit hits 500 Pa. In practice, this high pressure guarantees good airflow at the end.

Reference: AMCA 210 covers the test method behind these figures.

Technical Documentation

Drawing for LWA-200UM
First, the engineering drawing shows the 200mm unit dimensions.

Drawing for LWA-250UM
Next, engineers can read the 250W power draw details here.

Drawing for LWA-300UM
We provide the physical envelope for the 300mm design.

Finally, the catalog excerpt lists the ExdIIBT4 certifications.

Specifying a Portable Explosion-Proof Fan Properly

• First, check your site voltage before ordering fans. As a result, many job sites only offer 110V power carts. Standard industrial blowers often require 220V power. Moreover, you cannot easily use a step-up transformer in a gas area.
• Therefore, you must calculate the exact hose drag. In short, a long PVC hose adds huge air resistance. You cannot trust free-air performance numbers for ducted jobs.
• Next, verify the correct temperature group rating. Besides, your unit must stay cooler than the gas ignition point. An ExdIIBT4 rating keeps the surface safely below this limit.
• Finally, ask if the factory builds its own motors. Meanwhile, we make the explosion-proof motor and impeller in-house. This allows us to wind custom 110V stators very quickly.

Related: Axial Fans.

Common Questions About 110V Blowers

Browse our duct fans range, the inline duct fans section, or mixed flow fans.