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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
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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
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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
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How is a PSC motor different than an ECM?
PSC
ECM
vs.

• 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
AC Power
PSC
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
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Variable Speed vs. Constant Volume

• Variable speed motor will change or vary RPM.

• Constant volume will change or vary motor RPM to
  deliver a preset or programmed CFM.

What is the difference?
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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
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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 rotors 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
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How Does the ECM Sense Static Pressure?
Input Power vs. RPM
550
500
450
P kN3
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
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ECM Advantages

• Efficiency gain

Lower static pressure yields greater efficiency
gain
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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)
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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).

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Power Connectors

• Connectors are keyed
• Dont force in the wrong orientation
• Pull on the plug, NOT the cable
• DO NOT pull power cable out during
• operation Arching could occur

High Voltage 5 PIN CONNECTOR
Low Voltage 16 PIN CONNECTOR
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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
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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
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Troubleshooting ECM Motors
There are some ECM motor testers on the market
today.
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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.
• Dont judge the motor by the RPM or ramp up
  sequence.

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Troubleshooting ECM Motors

• Dont 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
Full capacity
Short run
Pre-run
Time 0 - 15 min, 16 steps Level 6 - 100 16
steps
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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
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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.

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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.
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Troubleshooting ECM Motors

• 5 Check inductor coil

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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)
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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.

16
Out
Out
Adjust /-
15
G(fan)
14
Y1
Y /Y2
13
Cool
EM Ht/W2
12
Delay
24VAC (R)
11
Common 2
Heat
10
W /W1
BK/PWM (Speed)
9
Common 1
(Rev Valve)
Control Connector Cable Half (viewed from
connector end)
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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 dont record voltage as noted, repeat test
  at control or interface board.

16
Out
Out
Adjust /-
15
G(fan)
14
Y1
Y /Y2
13
Cool
EM Ht/W2
12
Delay
24VAC (R)
11
Common 2
Heat
10
W /W1
BK/PWM (Speed)
9
Common 1
(Rev Valve)
Control Connector Cable Half (viewed from
connector end)
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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.

16
Out
Out
Adjust /-
15
G(fan)
14
Y1
Y /Y2
13
Cool
EM Ht/W2
12
Delay
24VAC (R)
11
Common 2
Heat
10
W /W1
BK/PWM (Speed)
9
Common 1
(Rev Valve)
Control Connector Cable Half (viewed from
connector end)
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Troubleshooting ECM Motors
16
Out
Out
Adjust /-
15
G(fan)
14
Y1
Y /Y2
13
Cool
EM Ht/W2
12
Delay
24VAC (R)
11
Common 2
Heat
10
W /W1
BK/PWM (Speed)
Should see 24 volts here
9
Common 1
(Rev Valve)
Control Connector Cable Half (viewed from
connector end)
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Troubleshooting ECM Motors
16
Out
Energize Fan Only Switch
Out
Adjust /-
15
G(fan)
14
Y1
Y /Y2
13
Cool
EM Ht/W2
12
Delay
24VAC (R)
11
Common 2
Heat
10
W /W1
BK/PWM (Speed)
Should see 12 volts here
9
Common 1
(Rev Valve)
Control Connector Cable Half (viewed from
connector end)
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thank you!
any questions?