A Huge Advantage of PMAC Motors in Hydronic Systems The PMAC motors are available up to 20-30 HP. The ECM motors today are limited to about 10 HP and get expensive above 5 HP. Part of the efficiency advantage of the ECM motor is that the external VFD efficiency also adds to the electrical usage. Just know that the PMAC motor needs a drive, and the ECM motor is the drive. I don’t want to get too far into the weeds here. A PMAC motor may use 150 Hz to dial the speed into 1800 RPM. The premium efficiency asynchronous 10 HP motor you currently specify operates at 60 Hz at the nameplate 1765 RPM. In a PMAC motor, the VFD is also needed to set the motor to its rated speed. The drive is needed to change the speed of the pump motor to control the flow rate or pressure differential. Our industry uses VFDs on most applications, so this is not a major change. The PMAC motor cannot work without a VFD. A PMAC motor requires a variable frequency drive (VFD). The ECM motors have electronics in them that allows you to change the speed manually or automatically. How Does a PMAC Motor Differ from the ECM Motors? The motor runs much cooler than our traditional AC motors. What this does give you is lower motor temperatures. This high torque is important in conveyer belts but of little value in hydronic pumps which are variable torque devices. This synchronous operation supplies more torque at low speeds. The rotor turns at the same speed of the changing magnetic field of the stator. This improves efficiency and makes the motor synchronous. No power is needed to create and maintain the magnetic field. It has a magnet in it and is always ready to start. This reduces the motor’s efficiency.Ī permanent magnet motor is just that. An 1800 RPM premium efficiency motor’s full load speed “slips” and could be around 1765 RPM. The motor uses a little of the AC power to create the magnetic field. This means that the full speed of the motor is slightly less than the nominal speed. The motors you normally specify on pumps are Asynchronous induction AC motors. How Does a PMAC Motor Differ from the Epact Premium Efficiency Motors? The ECM motors will trump the PMAC motors by another 1% or so. We see that the IE4 PMAC motors will increase the full load and full speed efficiencies by 1-2%. The current requirement for motors is the IE3 efficiencies. The IE5 Ultra-premium motors are mostly ECM motors. They may also be some of the ECM motors and pumps. The IE4 super premium motors are permanent magnet AC motors or PMAC. Our premium efficiency motors meet the IE3 classification. In 2014, the International Electrotechnical Commission(IEC) defined global efficiency classes for motors. These standards were only required for motors manufactured or used in the U.S.A. Our industry was introduced in two steps to the premium efficiency motors which are the standard of HVAC and plumbing specifications in the U.S. In the 1990s, the United States of America took a leadership position by instituting energy policy standards to improve overall motor efficiencies referred to as EPAct. International Efficiency Standards – a Very Short History In this article we define the ECM motor as a permanent magnet motor with the electronic circuitry built in to vary the speed of the motor. Visit “What are ECM Pumps and ECM Smart Pumps” for more information. A Smart pump has all this and some internal brains to do things on its own. Yes, the motor may have the ability to take a 0-10Vdc control signal and adjust the speed automatically. Yes, the speed of the motor, and thus the pump, can be manually adjusted. This does not make the pump a “Smart ECM” pump. The ECM technology can be incorporated into a pump. Visit “What is an ECM Pump” for more information. There is electronic circuitry which may allow the user to change the speed of the motor manually or automatically. The motor takes the AC voltage and converts it to DC inside of the motor. ECM is an electronically commutated motor. ECM Motors and Pumpsįirst, both ECM motors and PMAC motors have permanent magnets built into them. Some terms are used interchangeably in different industries so the examples I use today are all about, go figure, pumps. I want to focus today’s blog on motors used in hydronics and clean water plumbing. The terms, products, and values of motors tend to change with the application. When talking about motors, it is important to understand there are a variety of uses. Deppmann Monday Morning Minutes finished the year looking at these options. What is a PMAC motor? What is the difference between PMAC and the ECM pump motor? The R. One of the newer additions to motor options is the permanent magnet AC motor or PMAC. Hydronic system pumps and other HVAC and plumbing equipment will often have a variety of motor choices to specify.
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