Electric Motor Information and tips

Electric Motor Information and tips

We get a lot of questions about electric motors and how to match them up. 

CWSE or CCWSE = Clock Wise or Counter Clock Wise motor rotation 

If the shaft is pointing at you and rotates to the right, your motor is clockwise shaft end, or CWSE. If the shaft rotates to the left, your motor is counterclockwise shaft end, or CCWSE. 

How do I reverse the direction of a residential furnace motor?

  • Make sure that the motor you have is reversible. The nameplate on the side of the motor should tell you. Read the nameplate on the side on the motor and follow the directions for either clockwise or counterclockwise rotation. All motors come already set to either CW or CCW rotation, as you are looking at the shaft of the motor.

Remember when changing the motor and installing the blower wheel back on that you dont mistakenly turn the blower wheel around!! Double check to make sure the blower wheel fins are scooping the air and throwing it into the duct work. 

The fan motor is one of the hardest working components in your air conditioner and wear and tear will eventually take its toll. However, you can prevent it from burning out sooner than intended with regular HVAC maintenance.

One common reason an AC fan motor burns out is due to dirt building up around the fan motor. Dirt can creep into the holes of the motor, causing more friction for the inner workings which stresses the motor and causes overheating. Regular dusting in and around the motor hole can prevent this. This easy maintenance task helps prolong the lifespan of the fan motor and can prevent more serious AC problems.

If you’re not the most diligent person when it comes to HVAC maintenance, then the best way to ensure regular maintenance is to sign up for a maintenance plan with your HVAC company. Most maintenance plans include biannual HVAC tune-ups. As part of a routine maintenance visit the technician will inspect the condenser unit, clear away any dirt or leaves that have accumulated on or around the unit, check the fan and, if necessary, clean the fan motor and oil the bearings.

Understanding end play and its impact on axial alignment.

End play in an electric motor is the amount of axial movement allowed by the motor’s construction. This end play is limited by the motor’s bearing design. The bearing’s primary purpose is to locate the shaft radially so it can be aligned to the driven equipment shaft and efficiently transmit torque to the load. It is also important that the axial location be controlled such that the motor and driven equipment bearings are not subjected to excessive thrust or vibration and still have room for thermal growth of the shaft as it heats up during operation.

This can be accomplished by a number of ways depending on the design of the motor. If the motor has sleeve bearings, axial movement is expected within the limits of the bearing design.  Most rolling element bearings have much less axial clearance but must be contained in the bearing housing to control the end play.

Electric Motor Cross Reference

Some manufactures quit making motors and do not leave us a cross reference to another brand or model so this chart is what the engineers use to pick another brand to match up to use inplace of a no longer available motor.

You need to match match up:  (Example) in parentheses 

Must be exact match highlighted 

Nema Frame type  (42) Must be exact match.

Voltage (220 V)  Must be exact match.

Phase (1 PH)   Must be exact match.

Diameter (1/2")  Must be exact match.

HP  (3/4 HP)  Can Very 

Number Of Speeds  (2) Can Very

Motor Rotation  (CCW)  Must be exact match. You can determine shaft end perspective by simply holding your motor up in front of you and pointing the shaft at you. If the shaft is pointing at you and rotates to the right, your motor is clockwise shaft end, or CWSE. If the shaft rotates to the left, your motor is counterclockwise shaft end, or CCWSE.

Shaft length  (41/4")  Can Very most blower wheels are open hub so extra shaft can hang out the other side of the blower wheel, Or you can cut the excess off.  

Shaft Size Diameter (1/2") Must be exact match.

Single or Double shaft?  Must be exact match.

RPM (1075 RPM)  Can very but try to stay as close as you can to original 

Hope this guide helps you in the event of a motor replacement, If you need more help or have a question please email us colemanhvacparts@gmail.com 


Let us know if you have more questions! www.colemanhvacparts.com email us at colemanhvacparts@gmail.com