How to Cross-Reference an OEM Motor
Chris Beaton is the owner of eMotors Direct, an online electric motor retailer revolutionizing the way HVAC Technicians purchase their motor replacements. Their 45 years of experience, a team of motor experts, and access to North America's leading brands put a wealth of knowledge right at your fingertips.
How to Cross-Reference an OEM Motor
At the original installation, all HVAC equipment comes with the electric motors already installed. The OEM purchases motors from manufacturers you likely know to use in the design and build of their HVAC systems.
We know that electric motors are most often the reason an HVAC system is operating poorly or not at all. But that doesn’t mean you have to replace the whole system, you only need to find the OEM replacement for the motor.
Why Not Purchase From the OEM?
You purchased the HVAC system from them, why wouldn’t you go back to the original equipment manufacturer (OEM) for your motor replacement? There are a few reasons why you would choose to purchase your motor replacement elsewhere.
Save money – the OEM purchases the motor directly from the manufacturer. They then mark up the price to ensure that they also make money on the sale. You can save money by skipping the OEM of the HVAC equipment and going directly to the manufacturer or supplier of the motor.
Availability – By going directly to the motor supplier, you can save time by selecting a motor that is available asap. If the OEM of the HVAC system doesn’t have availability, they’ll need to order the motor before sending it on to you. In most cases, you should be able to find a replacement motor that can be shipped or picked up that day.
Brand Loyalty – You or your client may have a preferred electric motor brand and choose to have brand consistency across all stock. This isn’t necessarily about one brand being better than the other, it’s about decreasing your spare inventory. When you select one brand to work with, you no longer need to keep as many spares on hand for replacements.
Cross-Referencing OEM Motors
How do you go about finding the same motor but from a different brand? Here are two simple ways you can cross-reference your OEM motor to find direct replacements.
Manufacturer Model Number
The simplest, quickest, and most accurate way to cross-reference your OEM electric motor is by using the motor manufacturer’s model number. You’ll most often find the model number on the motor’s nameplate. Keep in mind, though, that many motor nameplates have a few different identifying numbers. HVAC system manufacturers might put their identifying numbers on the nameplate along with the motor manufacturer's catalogue and model numbers. Make sure that the number you are using to cross-reference is the motor manufacturer’s model number.
Once you find the number, you can provide it to your supplier or use an online cross-reference tool to find the motor’s direct replacements.
Can’t find the motor’s model number? You can match motor specifications instead. Gathering a few pieces of information like electrical ratings and physical dimensions will help you find the right replacement. Makes sure to collect as much information as possible and that you record the information correctly. One small error could have you ordering a motor that is completely wrong for the job at hand.
- Horsepower (HP)
- Voltage (V)
- Number of speeds
- RPM – record for each speed if the motor is multispeed
- Single-phase or three-phase
- Service Factor (SF)
- Direction of rotation
- Frame Size
- If you can’t find this on the nameplate, record the length and diameter of both the motor body and the shaft(s).
- Belly band
- Bolt through
Open air over (OAO)
Open drip proof (ODP)
Totally enclosed air over (TEAO)
Totally enclosed fan cooled (TEFC)
Totally enclosed non ventilated (TENV)
Single or double shaft
Additional Specifications to Look For:
- Will it be mounted in a hazardous location?
- Bearing type
- Motor type:
- Blower motor
- Fan motor
- Pump motor
- Compressor duty motor
- Draft inducer
- Building exhaust
Once you have collected all of the important information on the old motor, you can provide it to your supplier or use an online cross-reference tool to find the motor’s direct replacements.
Check out this podcast discussing operation of a few motors used in the HVAC industry
Cross-referencing your OEM electric motor isn’t as complicated as some might think. One simple identifying number might be all you need. And if you can’t find the motor’s model number, all the information you need to find the correct replacement is found right on the motor itself.
When replacing a belted motor, it's a good idea to set and check belt tension. This video explains how to use a belt tensioning tool.
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