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…just got better

…just got better. Understanding ECM Motors. What does ECM mean? Electrically Commutated Motor. The ECM Technology.

Mercy
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…just got better

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  1. …just got better

  2. Understanding ECM Motors What does ECM mean? Electrically Commutated Motor

  3. The ECM Technology The GE ECMTM motor is a brushless DC, Three - phase motor with a permanent magnet rotor. Motor phases are sequentially energized by the electronic control, powered from a single-phase supply.

  4. Control Construction • Microcomputer module • Power Conditioning module • Encapsulated with a polyurethane • compound to protect against moisture

  5. Stator Construction • Laminated, interlocked stator • Steel shell, aluminum end shield, • through-bolt construction • Inslot Salient wound • Available in closed, partial, or fully • vented shell

  6. Rotor Construction • 3 Iron Ferrite magnets glued on rotor sleeve • Magnetized at GE Factory • Two Resilient Rings isolate the shaft from the rotor • Ball Bearings

  7. ECM Modes of Operation Control Cont… • Thermostatic Control (TSTAT)...Most widely used in Residential systems • Discrete field selection of airflow settings and comfort options. • Direct 24 VAC interface to conventional thermostats • Supports 1 or 2 “stage” systems • Suitable for furnaces, heat pumps, and fan coils • 4 levels of cooling airflow + trim • 4 levels of heating airflow + trim • Enables use of 4 unique delay profiles Connects to Connects to Tap Board * Thermostat Motor • * OEM Specific

  8. Tap Boards (or interface boards) Purpose: Designed to convert one TSTAT input into up to 4 different field selectable outputs. • 4 Field selectable outputs for: • Heating • Cooling • Trim multipliers • Delay/Ramps • May also be used to enable Humidistat 24 VAC Input Selection Output full wave half wave - half wave + no signal

  9. How the Tap Board Communicates with the ECM 24 VAC Input Selection* Output full wave D half wave - C half wave + B no signal A * For Cool, Heat, Adjust, Delay

  10. Motor Motor How is a PSC motor different than an ECM? PSC vs. ECM • Start-up by contact to AC line • Controlled by AC line • Abrupt turn-on stress, noise • Motor speed taps are inefficient and produce only minor speed adjustment • Permanently connected to AC line • Controlled by low voltage inputs • Motor starts softly, ramps to speed • Wide and efficient airflow range between hi and low taps ECM PSC AC Power Inverter Power Conditioning AC to DC Conversion AC Power Relay Contacts Motor Control Interface Control Start / Run Capacitor HVAC System Control HVAC System Control INPUTS INPUTS Available Outputs 24 VAC Heat Call Heat Calls 24Vac RPM Capacity Select Constant Fan low stage Compressor Calls Delay selects OverSpeed Compressor Call low /hi / off hi stage Trim/Adjust UnderSpeed Constant Fan aux/emerg Rev Valve Humidistat CFM Demand

  11. Variable speed motor will change or vary RPM. Constant volume will change or vary motor RPM to deliver a preset or programmed CFM. Variable Speed vs. Constant Volume What is the difference?

  12. Airflow Control Tips For GE ECMTM • 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! Use good duct design practices and hold static pressure to less than .8”, ideally less than .5”

  13. Rotor Position Sensing • At any given time while the motor is running, two of the three phases are energized • The movement of the magnetized rotor past the third phase induces a voltage, • or back EMF, in this unenergized phase • The voltage in the third phase communicates the rotor’s position to the control • Motor Torque is regulated at a given • level by an accurate control of the • current in motor phases. • The microcomputer control keeps • torque constant regardless of • operating speed. Phase 1 Phase 3 Phase 2

  14. How Does the ECM Sense Static Pressure? Input Power vs. RPM 550 500 450 P = kN^3 400 1000 RPM 1/2 N = 1/8 P 350 280 Watts 300 1/8 X 280W = 35W Input Power (watts) 250 200 500 RPM 150 35 Watts 100 50 0 250 300 350 400 450 500 550 600 650 700 750 800 850 900 950 1000 1050 1100 1150 RPM

  15. ECM Advantages • Efficiency gain Lower static pressure yields greater efficiency gain

  16. 0.8 0.7 0.6 0.5 745W • ® 0.4 0.3 0.2 408W • ® 0.1 0 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 2400 ECM Advantages • Static-independent Airflow Set the airflow and go! • System airflow is starved • insufficient cooling/heating • liquid refrigerant return • to condenser • Over blowing the system • poor moisture removal • high power consumption • moisture in the duct work PRESSURE Typical profile with a PSC motor Airflow (CFM)

  17. Troubleshooting ECM Motors • The # 1 failure of ECM motors…………… No Fault Found ! (80%) • The # 2 failure of ECM Motors …………… Moisture. (16%) • All other failures (4%).

  18. Power Connectors • Connectors are keyed • Don’t force in the wrong orientation • Pull on the plug, NOT the cable • DO NOT pull power cable out during • operation – Arching could occur Low Voltage 16 PIN CONNECTOR High Voltage 5 PIN CONNECTOR

  19. Power Connectors Continued 5 Pin Power Connector • 120 VAC uses a jumper (red wire) • Control operates at 240 VAC • Jumper enables voltage doubler • Do not apply 240 VAC with jumper installed as motor and • control will fail. • 240 VAC input does not use a JUMPER 16 Pin Signal Connector • Pulse Width Modulation (PWM) or • 24 VAC Thermostat Mode or • Digital Serial Interface (DSI) Operating Voltages Application Note

  20. How Does the ECM Work? Motor Connector • The End Bell defines motor characteristics. • Only 3 motor sections ½, ¾, or 1 hp. • The motor is really a three phase motor with a permanent magnet rotor. Motor Section End Bell Assembly

  21. Troubleshooting ECM Motors There are some ECM motor testers on the market today.

  22. Troubleshooting ECM Motors What is Normal? • It is normal for the blower to rock back and forth at start up. • It is normal for the shaft to feel rough or bumpy when turned. • Don’t judge the motor by the RPM or ramp up sequence.

  23. Troubleshooting ECM Motors • Don’t judge the motor by the RPM or ramp up sequence. off All slew rates are controlled Profile A Profile B Profile C on Off Delay Short run Full capacity Pre-run Time: 0 - 15 min, 16 steps Level: 6 - 100% 16 steps

  24. Troubleshooting ECM Motors • Always make sure the motor is oriented such that the connectors are on the bottom • Make sure the electrical connections form a drip loop to prevent any moisture from running down the harness and into the end bell assembly. • A blower wheel loose on the motor shaft can cause the blower to vibrate, excessive noise, and may cause motor malfunction. Drip Loop Electrical Connections on Bottom

  25. Troubleshooting ECM Motors How do we troubleshoot ECM motors? • Rule # 1 – If the motor is running at all. The problem is not in the motor. • Rule # 2 – If the motor is running at the wrong RPM/CFM, the most likely cause is the installation or controls sending signals to the ECM motor. • Rule # 3 – What is the most common failure mode? Water. Look for signs of moisture damage and correct before replacing end bell.

  26. 5 4 3 2 1 Troubleshooting ECM Motors • Rule # 4 - ECM motors, like any motor must have a power supply. Check the incoming power supply. Inductor I AC Line Gnd Pin 1 & 2 must be connected together for 120Vac input applications AC Line } V } Power Connector (viewed from plug end) Inductor is used on ¾ & 1 hp – 120 VAC applications only.

  27. Troubleshooting ECM Motors • # 5 Check inductor coil

  28. TSTAT Connections Pin number 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Common C1 W/W1 Common C2 Delay tap select Cool tap Select Y1 Adjust tap select Output - Return valve (heat pump only) Humidistat (BK) Heat tap select 24 VAC (R) 2nd stage heat (EM/W2) 2nd stage cool (Y/Y2) Fan (G) Output + 9 10111213141516 12345678 Connector (female) Control (male)

  29. 8 7 6 5 4 3 2 1 Troubleshooting ECM Motors • Rule # 5 - ECM motors, like any motor must have a signal or switch to turn it on, or tell it to run. • Controls should be checked with a true RMS meter or analog meter. • Controls will activate at ½ nominal voltage and 12 milliamps. Out 16 Out + Adjust +/- 15 G(fan) Y1 14 Y /Y2 Cool 13 EM Ht/W2 Delay 12 24VAC (R) Common 2 11 Heat W /W1 10 BK/PWM (Speed) Common 1 9 (Rev Valve) Control Connector Cable Half (viewed from connector end)

  30. 8 7 6 5 4 3 2 1 Troubleshooting ECM Motors • Check power to control. Pins 1 to 12 and 3 to 12. You must have 24 VAC. • Set thermostat to demand for cooling. Check for 24 VAC at pins 1 to 6 and 3 to 6. • If you don’t record voltage as noted, repeat test at control or interface board. Out 16 Out + Adjust +/- 15 G(fan) Y1 14 Y /Y2 Cool 13 EM Ht/W2 Delay 12 24VAC (R) Common 2 11 Heat W /W1 10 BK/PWM (Speed) Common 1 9 (Rev Valve) Control Connector Cable Half (viewed from connector end)

  31. 8 7 6 5 4 3 2 1 Troubleshooting ECM Motors • If control is defective, remove end bell and inspect for moisture before replacing control board. • Do not apply power to pins 8 or 16. • Do not apply line voltage to control connections. Out 16 Out + Adjust +/- 15 G(fan) Y1 14 Y /Y2 Cool 13 EM Ht/W2 Delay 12 24VAC (R) Common 2 11 Heat W /W1 10 BK/PWM (Speed) Common 1 9 (Rev Valve) Control Connector Cable Half (viewed from connector end)

  32. 8 7 6 5 4 3 2 1 Troubleshooting ECM Motors Out 16 Out + Adjust +/- 15 G(fan) Y1 14 Y /Y2 Cool 13 EM Ht/W2 Delay 12 24VAC (R) Common 2 11 Heat W /W1 10 BK/PWM (Speed) Should see 24 volts here Common 1 9 (Rev Valve) Control Connector Cable Half (viewed from connector end)

  33. 8 7 6 5 4 3 2 1 Troubleshooting ECM Motors Energize Fan Only Switch Out 16 Out + Adjust +/- 15 G(fan) Y1 14 Y /Y2 Cool 13 EM Ht/W2 Delay 12 24VAC (R) Common 2 11 Heat W /W1 10 BK/PWM (Speed) Should see 12 volts here Common 1 9 (Rev Valve) Control Connector Cable Half (viewed from connector end)

  34. any questions? thank you!

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