ECM Motor close up

As an HVAC business owner, you know that most people involved in HVAC and refrigeration work with electric motors, such as an ECM motor, almost every day. There is no doubt that the technology and science behind air conditioning and heating are quickly advancing. One of the main goals of the latest HVAC research is to find better ways to increase the energy savings and efficiency of systems.  

Also, note that energy savings and efficiency are not just an important way for business owners and homeowners to save considerable money, but they also benefit our environment. Did you know that Electronically Commutated Motors (also known as ECMs) was designed and developed to provide the user with a greater range of operability choices? You will be pleased to know they also minimize noise and are quieter. Note that ECM motors use electronic controls to vary their speed.  

Whether specifying equipment, designing new products, installing, repairing, or maintaining various heating, ventilation, or cooling products, electric motors and their needs are often the centers of attention. And it is worth noting that when working with ECM motors, a thorough and comprehensive knowledge of safety procedures can save your contractors from serious injury as well as prevent damage to valuable equipment.

You should know the safe operation of an electronically commutated motor requires the careful and meticulous observance of all the safety rules, such as safe installation and proper handling.

What is an ECM Motor?

photo of a EDM Motor

ECM is a motor that uses electronic controls to vary its speed.  Did you know that the construction of an ECM motor system is usually quite similar to that of a PMSM (Permanent Magnet Synchronous Motor)? However, it may also be an induction (asynchronous) motor or a switched reluctance motor. There are three main types of ECM motors. These are constant RPM,  CFM, and torque. As RPM, CFM, and torque are all related, note that the basic principles are usually the same.

How does an ECM motor work?

Note that an ECM motor adjusts or changes its speed in response to frequently changing conditions to maintain a programmed CFM. So, when it senses a change in torque, the ECM motor ramps the RPM down or up to compensate.  It is worth noting that ECM motors are a kind of DC motor.

These motors are also known as EEM fan motors, DC fan motors, and variable speed motors. ECM motors function using a magnet rotor and a built-in inverter. This is why they can achieve more efficiency in airflow systems than many types of AC motors.

You should know that different conditions can affect CFM. For example, in cooling mode, duct issues, a wet evaporator coil, and a dirty filter will increase static pressure. The ECM motor senses this change in static pressure and responds by increasing RPM.  

On the other hand, when the dirty filter is replaced, or there’s less moisture on the coil, then the ECM motor will decrease RPM. Also, note that during heating, the ECM motor will provide the needed CFM in order to maintain temperature and will also adjust RPM accordingly.

Are ECM motors reliable?

As an HVAC business owner, you may know that there is a trend in the industry to use ECM motors instead of other AC motors. Did you know that some of the most significant reasons to switch to an ECM motor are the remarkable reduction in power needed to operate them and more reliability versus a standard AC motor? 

ECM motors are not only affordable and straightforward, but they have proven to be a very reliable and sturdy component. Most PSC motors’ average lifespan is about 40,000 hours, while ECM motors have an average lifespan of 90,000 hours

Due to its variable speed settings, note that the energy needed to power an ECM motor can be raised or lowered according to demand. Also, the motor will never run at a higher speed than necessary. The ECM motor can easily adjust its speed and save considerable energy when the condenser fan does not have to run at full speed.

What is the difference between an ECM motor and a PSC motor? 

a device testing out the electrical wires of EDM Motor

A permanent split capacitor (PSC) is a kind of electric motor that is driven only by one AC current and not 3 offset currents. And because these motors operate at one constant speed, the utilization of energy is constant. This is why they lose efficiency. The most notable difference between these two models is that PSC motors have one speed: their full speed. So, any time the blower is working, note that it blows at full force.

On the other hand, the ECM motor is a variable speed model that can adjust the airflow to an optimal level based on a home’s desired temperature. ECM motors save energy while improving the efficient movement of air through a unit.

Benefits of ECM motors

Wider Operating Range

Did you know that ECM motors have a considerably wider operating range compared to traditional induction motors? And this means that just a single ECM motor can easily replace several induction motor models. This is how the number of models a customer requires is significantly lower, thus decreasing and simplifying inventory.

High Efficiency

Another big advantage of using ECM motors is that they are considerably more efficient than AC motors. And it is worth noting that ECM motors can maintain a high level (65% to 75%) of efficiency at various speeds. Note that this is simply not true for AC motors that operate on variable frequency drives. This is why ECMs are energy and cost efficient and can lower operating costs. 

Issues with ECM motors and safety

ECM motors come with their unique issues and problems. Consider a marginal system that has higher-than-standard static pressures. For instance, in a .4–in TESP rated furnace with an ECM motor on a .7–in. TESP system, the ECM motor, still might maintain suitable airflow close to design. However, note that the tradeoff is usually higher velocities that often cause a noisy system and even some coil blow-off.  

It is also worth noting that the additional torque often needed to overcome the higher statics triggers higher electrical consumption. This can lower actual equipment EER (Energy Efficiency Ratio), meaning that your customers will not enjoy the energy savings that the pairing of high-efficiency components can yield.

Some disadvantages of these ECM motors are as follows:

  • The friction of the brushes that slide along the rotating commutator segments can cause power losses. These losses can be significant, especially in low power motors.
  • Did you know that the soft brush material tends to wear down because of friction? This creates dust, and eventually, you will have to replace the brushes. This also makes ECM motors unsuitable for many sealed or low particulate applications. Some of these applications are hard disk motors. It is also not suitable for applications that usually require a maintenance-free operation.
  • Note that the resistance of the sliding brush contact triggers a voltage drop in the ECM motor circuit. This is called a brush drop and consumes energy.

Other Safety Risks

The regular abrupt switching of the current via the inductance of the windings can cause sparks, especially at various commutator contacts. This is a severe fire risk in explosive atmospheres and is also a source of degrading and harmful UV radiation. These are two important reasons why your contractors should have caution when using an ECM motor.

The sparks are also a source of electronic noise, causing electromagnetic interference in any nearby microelectronic circuits. This is why your contractors should be cautious when using ECM motors.

Some other consequences and ramifications of high static installations can include noise at the registers emanating from high air velocities. Did you know that in some extreme cases, filter media may be sucked out of the rack? This can cause the filter bypass. In other extreme cases, filter media might get pulled into the fan and chopped up. Filter media can also blow through the system and cause all types of damage. So, exercising caution is of paramount importance for people operating ECM motors.

Are ECM motors quieter?

An ECM motor’s higher efficiency means that these motors run “cool.” This can dramatically lower the amount of waste heat generated. Also, keep in mind that high efficiency will allow for further energy savings. An ECM motor is also quieter than conventional inefficient motors and has a longer design life. Also, these motors require less maintenance.

So, an electronically commutated motor provides the flexibility and technology to ensure quiet, smooth, and efficient delivery of suitable airflow at all time. And in terms of features, as these motors are controlled by software, they allow customers to easily optimize as well as integrate the motor, controller, and fan with the furnace. They also have features like volume control, data communications, and variable speed, etc.

Final thoughts

ECM motors are used heavily in the HVAC industry. While they offer many benefits, you have to ensure that your contractors use them safely. It is likely that your HVAC company is a local business, and typically, customers search for local contractors. This is why you should leverage Google My Business to grow your business. Use these tips to collect more reviews for your HVAC business on Google My Business. You can use Podium to improve your overall customer experience with sentiment analysis, reviews, messaging tools, Webchat, and a lot more. Enhance your communication strategy to take your HVAC business to the next level.

You can try out Podium today for free.

Jennifer Wilson
Jennifer Wilson Strategic Home Services Account Executive

Jennifer Wilson is a home services professional at Podium, the premiere messaging platform that connects local businesses with their customers.

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