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ECM-Driven Systems Industrial Systems How’s the GE ECM™ Motor different than an Induction Motor? • Operation • Construction • The ECM’s Electronics The ECM's Benefits and Advantages in HVAC • Efficiency • Constant Airflow • Tailoring to the Customer • Sound • Programmability Installation and Serviceability • Troubleshooting ECM-Driven Systems • Set-up • Replacing the Control Module • Troubleshooting Guides • Frequently Asked Questions GE ECM Motor is a trademark of the General Electric Company ECM-Driven Systems Industrial Systems What's an ECM? The highest efficiency motor there is! … A DC Motor Without mechanical Brushes and Commutator Permanent Magnet Rotor Rotor losses are nearly zero Stator is driven from an Inverter, which, in turn, is powered from the AC line The “Electronic Inverter” “Commutates” the stator magnetic fields Synchronous machine Speed and torque controlled Interfaces to the HVAC controls ECM-Driven Systems How’s an ECM Industrial Systems Different Than a PSC Motor? The Rotor Stator current produces magnetic field that acts on rotor: Permanent magnets on rotor oppose stator field No current flows in rotor Rotor losses are very low Torque is controlled by adjusting current in stator Resilient isolation from shaft Stator current produces magnetic field that acts on rotor: Rotor “slips” in stator-produced field, inducing currents in rotor Rotor currents create magnetic field to oppose stator field Current in rotor causes I2R losses and heat Limited torque control ECM-Driven Systems How’s an ECM Industrial Systems Different Than a PSC Motor? Operation and Application Controlled by low voltage inputs Controlled by AC line Permanently connected to AC line Motor starts softly, ramps to speed Wide airflow range between hi and low taps AC Power Power Conditioning AC to DC Conversion Inverter Start-up by contact to AC line Abrupt turn-on stress, noise Motor speed taps are inefficient and produce only minor speed adjustment ECM Blower Motor AC Power Relay Contacts PSC Blower Motor HVAC System Control INPUTS 24Vac Fan On Rev Valve Compressor Call Heat Call Capacity Select Delay selects Trim/Adjust Humidistat Available Outputs RPM OverSpeed UnderSpeed CFM Demand Motor Control Block Diagram - ECM Motor & Control start/run capacitor HVAC System Control INPUTS 24Vac Compressor Calls low/hi//off Continuous fan Heat Calls low stage hi stage aux/emerg Motor Control Block Diagram - PSC Motor & Control ECM-Driven Systems Industrial Systems The ECM’s Benefits in HVAC Constant Airflow In a series of tests the motor is “taught” the relationship between speed, torque, airflow and external static pressure. “Airflow” is Programmed by the HVAC OEM and is specific and unique to the motor and air mover combination Airflow is easily set up and trimmed at the installation Uses an “Interface/Tap Board” and jumper or dip-switch settings No other motor offers so many ways to control comfort and efficiency Be sensitive to your customer …. “tailor” the airflow for him/her in his/her unique installation Capitalize on the unmatched flexibility of ECM-driven air movers ….. Offer “Tailored Comfort”. ECM-Driven Systems Industrial Systems The ECM’s Benefits in HVAC ECM Airflow Control Constant airflow over wide external pressure changes Greater customer comfort and satisfaction PSC External pressure change causes: airflow variation as filter loads reduced performance poor latent/sensible capacity control PRESSURE Set the airflow level and go! System airflow is starved Overblowing the system • poor moisture removal • high power consumption ECM-Driven Systems Industrial Systems The ECM’s Benefits in HVAC Efficiency PSC motor: ECM: At 0.15” ESP (DOE rating point): 2x the efficiency of the PSC At 0.5”ESP (typical applied condition): 40% greater than PSC 550 3 speed PSC Induction Motor 500 450 Input Power (Watts) optimized only at rated design conditions highest operating cost under most applied conditions. 400 350 Induction motor needs over 100 Watts more power than GE ECM 280 Watts 300 250 Cut speed in half, cut power by a factor of 8. 200 150 100 35 Watts Variable Speed GE ECM 50 0 250 300 350 400 450 500 500 550 600 650 700 750 800 850 900 Motor Speed (RPM) 950 1000 1000 1050 1100 1150 1200 ECM-Driven Systems Industrial Systems The ECM’s Benefits in HVAC Constant Airflow - How does the motor know what to do? 1200 E Speed (RPM) 1000 D High Static Pressure C 800 B 600 Low Static Pressure 400 A 200 Constant Airflow Profile (800 cfm) 0 0 10 20 30 40 50 60 70 Normalized Motor Torque (%) 80 90 100 ECM-Driven Systems Industrial Systems How the GE ECM™ Makes Airflow Constant Unlike a conventional induction motor, GE’s ECM motor regulates itself by automatically changing torque and speed to maintain a programmed level of constant airflow over a wide range of external static pressures. This is accomplished through several steps. First, the air-moving system is characterized in an airflow chamber for its torque and static pressure operating range. That characteristic is then programmed into the motor. Then the motor's control is programmed with a set of desired airflows (e.g. 800 cfm). That constant airflow is defined by the ECM's speed and torque, which is expressed in the graph nearby as the orange line. Point A on the orange line, for instance, represents an airflow of 800 CFM at the initial level of static pressure in the system, here called Low Static Pressure (see the green line). As long as the pressure remains constant, the ECM motor will continue to deliver 800 cfm to the system. This is referred to as a stable operating point which is defined as any point where the system profiles intercept the ECM constant airflow profile. Points A and E in this example are the only stable points for constant airflow in the graph. If static pressure changes (for example, a clogged air filter, or different installation), then the blower speed will increase to Point B (see High Static Pressure Curve, blue line). This increase in speed occurs when any blower––whether equipped with an ECM or AC induction motor––encounters an increase in static pressure. The reason is that the clogged filter restricts airflow in the system meaning there is less air for the blower to propel through the system. (This is akin to a car's wheels losing traction on ice and spinning freely). The airflow at Point B, however, is lower than required to remain on the desired Constant Airflow Profile as expressed by the orange line. The motor will not operate at Point B because its programming does not allow this combination of torque and speed for this particular system. As a result, the GE ECM patented algorithm will increase torque and speed to find a new stable operating point on the High Static Pressure Curve. Increases in torque will continue until the speed and torque converge with the next stable operating point, which in this case is Point E on High Static Pressure Curve. When operating a point E, the blower is delivering higher torque, higher speed, but the same airflow as in point A. © 2000 General Electric Company ECM-Driven Systems Industrial Systems The ECM’s Benefits in HVAC The ECM’s Sound Advantage Air noise dominates at high airflow, but ECM still has a slight advantage At ~70% of rated airflow ECM is ~6 times quieter than at max airflow • PSC motor at rated - 58.4 • ECM motor at rated airflow • ECM (512rpm) • ECM (600rpm) (free discharge) 50 40 30 20 10 Overall DBA: airflow 60 Sound level (Db) ECM can get to lower airflow than PSC Tone levels of ECM & PSC motors - 58.1 - 39.4 - 44.0 0 100Hz 125Hz 200Hz 250Hz 500Hz 800Hz 1000Hz 1250Hz 1600Hz 3150Hz 6300Hz Frequency (1/3 octave avg.) ECM@1106RPM PSC @1050RPM ECM@512 ECM@600 At low airflow, ECM has clear sound advantage over all other motor technologies (>14db quieter at ~1/2 capacity) ECM-Driven Systems Industrial Systems The ECM’s Advantages For the Equipment Manufacturer Improved system performance Optimum performance and efficiency at design and rating conditions Customer-tailored airflow at part load Standardized motors and controls leverage volume and reduce inventory Reduced engineering development time Programmability GE-supplied development system simplifies application GE application support ECM-Driven Systems Industrial Systems The ECM’s Advantages For the Contractor Flexibility Used with conventional 1-stage, 2-stage or variable capacity T‘stats Conventional 24VAC interfaces Field adaptable and serviceable Wide cfm selection …. PLUS trim Constant cfm simplifies installation Capable of delivering proper airflow into applications with higher restriction Replaceable controls make ECM repairable for the same price as replacing induction motors Satisfied Customers Perceptible, Saleable performance and comfort Tailor airflow to the customer’s preferences Improve latent/sensible control ECM-Driven Systems Industrial Systems The ECM’s Advantages For the Homeowner Lower operating cost Greatest applied efficiency of any system Low stage and continuous fan airflows cost pennies to operate Higher comfort Low sound level Soft start-up Virtually silent low stage in 2-stage systems Precise airflow gives better humidity/discharge temp control Better filtration Satisfaction in quality Perceptible performance and comfort ECM-Driven Systems Installation and Service ECM Connections 5-Pin power connection 16-Pin control connection Connector housing and control openings are “keyed” – properly insert connectors Don’t let water run into connectors or openings Be careful when probing connector and motor pins Familiarity with ECM-to-system interface aids troubleshooting Industrial Systems ECM-Driven Systems Industrial Systems Installation and Service Power Connection TIPS ECMs connect directly to the line Do Not insert contactors/relays in series with either AC line Control is powered continuously insures reliable start-up maximizes reliability Pins 1&2 are jumpered in harness for Furnace (115V) operation Line voltage should NEVER be applied to pins 1 or 2. 5 4 3 2 1 AC Line AC Line Gnd Lines 1&2 will be connected for 120Vac applications only Make sure power is OFF before inserting or removing power connector Verify and re-verify connector orientation before applying power Plug is Polarized Do Not force plug into motor ECM-Driven Systems Industrial Systems Installation and Service Power Connection TIPS 5 4 3 2 1 Furnaces/115Vac applications require series inductance in AC line All 3/4 and 1hp applications will use inductor, 1/2hp may not Reason: AC line currents are nonsinusoidal Inductor reduces peak line current Maintains circuit “ampacity” Inductor should always be in line (HOT) side. AC Line AC Line Gnd Lines 1&2 will be connected for 120Vac applications only True RMS meters should be used to measure line current Some clamp-on ammeters may not read line current accurately. Remember -- the ECM’s current will be very low at off-load conditions because of its high efficiency. ECM-Driven Systems Industrial Systems Installation and Service Low Voltage Connections Through the 16-Pin Connector for cooling mode latent/sensible capacity control ECM-Driven Systems Industrial Systems Installation and Service Control Connection Tips 24 VAC Inputs operate motor - like a conventional system Functions G, Y, Y1, Y2, O, W will activate from 24Vac (R) • Jumper R to G to activate fan at fan-only speed • R to G to Y will activate fan to cooling speed G, Y, Y1, Y2 are on a threshold of 1/2 the “R” voltage. Stats that “steal” power through Y or other functions are NOT compatible Some solid state relays cannot turn off G and Y. Don’t apply high voltage to control pins Don’t apply 24Vac to Out+ or Out- ECM-Driven Systems Industrial Systems Installation and Service Control Connection Tips Make sure connector is fully seated Make sure pins from harness are fully inserted into connector Make sure transformer common(C) is tied to C1 and C2 Pins 5, 11, 7, 4 access four Tables programmed into the motor: • Heat Airflow • Cool Airflow • Start/Stop ramps and delays • Airflow Adjust or Trim Don’t apply high voltage to control pins Don’t apply 24 Vac to Out+ or Out- ECM-Driven Systems Installation and Service Set Up TIPS Use the manufacturer’s service and installation documents to set-up the system Airflow VALUE (based on system capacity) must be set by switches Adjustments to the cooling airflow are made All of the motor connections should be understood Industrial Systems ECM-Driven Systems Industrial Systems Installation and Service Equipment Manufacturers use a variety of interface and set-up techniques: Shunts/Jumpers Dip Switches Set-up must be done for ECM-driven systems to operate properly. ECM-Driven Systems Industrial Systems Installation and Service Set Up TIPS Changing: Heating airflow Cooling Off delay Cooling airflow require the unit to be cycled before the change takes effect off Cooling Adjust or Trim changes take effect immediately ECM-Driven Systems Industrial Systems Installation and Service Control Connection Tips Interface/tap boards select the system’s airflow capacity and operating profiles. Heating airflow @ pin 11 of ECM Cooling airflow @ pin 5 of ECM Profiles/Off-delays @ pin 4 of ECM Airflow trim at pin 7 of ECM These settings must be made for the system to operate properly. ECM-Driven Systems Installation and Service Control Signal Measurement Tips True RMS meters should be used Presence of half-wave signals from interface board can be determined Industrial Systems ECM-Driven Systems Industrial Systems Installation and Service What If… … “Y”, ”G”, ”W”, ”W2” are all off but the ECM is still running? ... Now what?? … the changeover valve signal (“O”) is not connected in a conventional air handler, so why is is it in an ECM-driven Air Handler? … “Y” is not connected in the blower’s low voltage control box. What will the cooling CFM be? … the dip-switch settings on the interface card are not changed at installation? … dip-switches controlling cooling and heating capacity are changed but the CFM doesn’t change! … there is no 24Vac on pin 12 of the ECM’s 16 pin connector? ECM-Driven Systems Industrial Systems Installation and Service What If answers… … “Y”, ”G”, ”W”, ”W2” are all off but the ECM is still running? ... Now what?? The system is probably being controlled by a thermostat that uses solid state relays or triacs as output switches. The current leaking through such switches can cause a voltage level to appear on the ECM Motor’s terminals that make it react as if the thermostat is actually calling. Another cause could be a high impedance compressor contactor or fan relay coil that causes a voltage above one-half the control transformer output voltage to appear on terminals “Y” or “G” of the motor. … the changeover valve signal (“O”) is not connected in a conventional air handler, so why is is it in an ECM-driven Air Handler Unlike induction motor-driven systems, ECM driven systems tailor airflow in heating and cooling with separate airflows for each. The ECM needs to know the mode in which the system is operating to select the proper airflow. ECM-Driven Systems Industrial Systems Installation and Service What If answers… … “Y” is not connected in the blower’s low voltage control box. What will the cooling CFM be? If “Y” is not connected, the ECM-driven blower will only respond to the “G” terminal in cooling. This means the blower will only operate at the “FANONLY” air volume and will not change to the “Cooling” airflow required during compressor operation. The system will probably trip-off on high compressor head pressure or, if there is sufficient airflow to prevent that, the system’s capacity will be seriously degraded and will cause system reliability degradation and comfort complaints. … the dip-switch settings on the interface card are not changed at installation? The dip switches on the interface card select airflow to match the size of the system installed. If they are not verified to be in the position matching the size of the condensing or heat pump unit, the indoor airflow will be grossly over-blown or under-blown. Also, the DELAY and TRIM functions will remain in factory default positions and may not be appropriate to the customer’s home, preferences or lifestyle. ECM-Driven Systems Industrial Systems Installation and Service What If answers… … dip-switches controlling cooling and heating capacity are changed but the CFM doesn’t change! In all probability, the switches were changed while the ECM-driven blower was running. The blower must go through an off-cycle for the new settings to take effect. … there is no 24Vac on pin 12 of the ECM’s 16 pin connector? Without 24VAC from the low voltage transformer present at pin 12 of the ECM, the motor will not respond correctly to most of the control functions; specifically, “O”, “Y1”, “Y/Y2”. It is important that in all systems depending on these inputs that “R” be connected to pin 12 of the ECM. The “Analyzer” troubleshooting tool can pin-point that problem, if it exists. ECM-Driven Systems Industrial Systems Installation and Service Constant Airflow TIPS Air Volume vs Ext SP ECM airflow programs are specific to the motor, blower and cabinet combination — DO NOT • Don’t exchange between different OEM products • Don’t exchange between furnaces and air handlers Cu Ft/min EXCHANGE ONE MOTOR MODEL WITH ANOTHER 1-ph PSC Lo 1-ph PSC Med 1-ph PSC HI 1700 1600 1500 1400 1300 1200 1100 1000 900 0.0 0.2 0.4 0.6 0.8 Ext Static Pressure (" H2O) CFM - NOT SPEED - is commanded by the controls -- G, W, Y, Bk, etc… Speed and torque change to hold CFM constant over a broad range of external static pressure 1.0 ECM ECM-Driven Systems Industrial Systems Installation and Service Constant Airflow TIPS Low static, high quality ducted applications will run slowly, quietly and efficiently….. while delivering the correct airflow. High static applications will run fast, be noisy and power hungry…. The ECM may still provide the correct airflow, but at a price! ECM-Driven Systems Industrial Systems Installation and Service Constant Airflow TIPS The ECM can help a distribution problem, but BEWARE of EXTREME CASES! Sometimes a problem can only be fixed at its source! • Talk to homeowner about his ductwork The motor program limits torque when a certain speed is reached High static pressure will activate the torque limit The motor will slow and airflow will fall off In extreme cases huffing may occur Solution -- Reduce the restriction!!! Take out high pressure drop filters Look for a problem in the #1 problem site in HVAC systems the air distribution system ECM-Driven Systems Industrial Systems Installation and Service TIPS on Isolating the problem Verify blower wheel is free and tight. Verify line voltage at control connector -- both lines and ground. Use the HVAC SYSTEM and ECM ANALYZER to isolate the problem to the motor or controls. ECM-Driven Systems Industrial Systems Installation and Service TIPS on Replacing the Control Module If the motor doesn’t run ... Check out the motor per the procedure in the equipment manufacturer’s literature or GED7161 If the motor’s good, replace the Control only... It’s cheaper and it’s faster! Use the correct replacement module While you’re there, look for other evidence -- Any Water? If replacing an ECM2 control, use the Thru-Bolts and locater TAB that come with the replacement control Make sure the control housing is centered and flush with the motor end-shield Don’t over tighten - snug will do!