The Curse of the Cutoff Plate

April 10, 2023

Motor Minute™ Technical Tip – The Curse of the Cutoff Plate

Hi, Chris from Regal Rexnord here with your Motor Minute technical tip. Helping you become an HVAC motor pro one minute at a time.

Today’s Motor Minute technical tip is “The Curse of the Cutoff Plate.”

You are probably wondering, what is the cutoff plate, and what does it have to do with motors? The cutoff plate is the piece of sheet metal located in the outlet of the blower housing that you would need to remove if you wanted to remove the blower wheel from the housing. So now you are asking yourself, why do I need to remove the blower wheel to replace the motor? The simple answer is, you don’t. But…

When replacing an indoor blower motor, you have done 75% of the work needed to clean the blower wheel. And let's be honest, the blower wheel is likely in need of a cleaning. Providing the customer with a clean blower wheel is a great value-added service. It’s also a fantastic way to show the customer that they are in need of a better filter, and possibly a maintenance program, which I am sure your company encourages you to offer.

Now, you may be wondering, what’s the curse? The curse is forgetting to re-install the cutoff plate. Without the cutoff plate installed, there will be significantly less airflow. It looks like there should be more airflow. However, the majority of the air will simply recirculate around the blower housing instead of exiting the outlet.

The missing cutoff plate will cause low airflow performance issues that will make you scratch your head until you look down and see said cutoff plate lying on the floor. This will remind you that now you have to remove the blower housing, again, to re-install the cutoff plate.

Tip #1 – Place the cutoff plate somewhere you won’t forget to install it.

Tip #2 – Install the cutoff plate in the correct orientation. The plate should conform to the shape of the blower housing.

Tip #3 – Install the cutoff plate correctly. Make sure the edge is secured in place, the orientation is correct and install both screws.

And that’s a wrap on this segment of Motor Minute technical tips. Remember that we provide motor training and product information in multiple formats including videos, literature, podcasts, articles, of course Motor Minute technical tips and classroom education both online and face to face. All of this industry leading training is available at no charge to HVAC professionals at regalmmu.com. Thank you for taking the time to build your motor knowledge.