Ecm Motors - Trane UniTrane Installation, Operation And Maintenance Manual

Diagnostics and Troubleshooting

ECM Motors

WARNING
Hazardous Voltage w/Capacitors!
Failure to disconnect power and discharge capacitors
before servicing could result in death or serious injury.
Disconnect all electric power, including remote
disconnects and discharge all motor start/run
capacitors before servicing. Follow proper lockout
tagout procedures to ensure the power cannot be
inadvertently energized. For variable frequency drives
or other energy storing components provided by Trane
or others, refer to the appropriate manufacturer's
literature for allowable waiting periods for discharge of
capacitors. Verify with an appropriate voltmeter that all
capacitors have discharged.
For additional information regarding the safe discharge
of capacitors, see PROD-SVB06A-EN
An electronically commutated motors (ECM) is a closed
loop system that has equipment protections and envelope
enforcements. Do not assume that the motor has failed
without first consulting the VelociTach engine status/
diagnostics screen. In many cases, the engine shuts down
the motor operation and locks it out to prevent equipment
damage.
Electric heat operation and changeover coil control on
CSTI units are coordinated by the VelociTach motor control
board. Changeover function on Tracer
be affected by incorrect configuration of the VelociTach
motor control board or improper wiring of terminals to
analog input 1 on the Tracer® ZN controller (polarity
sensitivity).
The mini-access lid on the front of the main control panel
lid has the VelociTach troubleshooting/setup guide affixed
to the back of the lid. This guide is unit-specific and should
be consulted before determining the disposition of a unit.
The adapter boards contain high voltage. Configuration
adjustments to the VelociTach board should be made
through the SMALLER of the two low-voltage lids on the
front of the control panel, through the low-voltage
insulation/shielding.
WARNING
Hazardous Voltage!
Failure to disconnect power before servicing could
result in death or serious injury. Disconnect all electric
power, including remote disconnects before servicing.
Follow proper lockout/tagout procedures to ensure the
power can not be inadvertently energized.
General Information
The VelociTach motor control board oversees and
monitors all motor operations and changes to speed
resulting from:
150
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Note: In some cases, indirect requests will result in fan
The VelociTach motor control board also coordinates the
operation of electric heat, electric/hydronic heat lockouts,
and CSTI changeover coil operation.
Troubleshooting Tips
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®
ZN units can also
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Direct fan speed requests
– Customer fan speed switches
– Thermostat fan speed, On or 0–10V requests
– Automatic fan request from Tracer® ZN / UC
controllers
Indirect fan speed requests
– Electric heat requests will bring the fan to the
proper speed.
Conflicting fan speed requests
– If two or more commands are received (direct or
indirect), the fan will honor the higher speed
requested.
behavior change regardless of whether the end-
device fails to actuate (due to device failure, or
safety/down-stream lockouts).
VelociTach motor control board configuration must
perfectly match the factory-supplied ECM.
– Refer to "Adjustments, " p. 72
the motor control board.
The VelociTach motor control board will display
troubleshooting information, and contains dual
tachometers to aid in performance verification.
Under normal circumstances, the VelociTach display
will display the operational status of the motors and
electric heat circuit/sensors, however, a malfunction
will drive a priority display mode that will present the
error code instantly to the screen. The error must be
cleared by solving by powering down, removing the
cause of the problem and restarting the engine board.
VelociTach label (see "Motor control board label, "
p. 76) setup document (affixed to the back of the low
voltage access lid) should be used to verify engine
configuration settings.
For proper operation of the system, all plugs must be
firmly seated in all boards and motors. Insecure
connections will cause malfunction and the system
will shutdown.
Do not unplug or plug-in motors or connectors while
the system is receiving a speed request of any kind.
The system must be powered down before plugging or
un-plugging connections to the adapter boards,
engine boards or motors. Failure do so will register
diagnostics or cause unsafe operation and reduction in
the contact life of the connectors.
The motor will not spin if plugged in while the ECM
engine is requesting power.
for configuration of
UNT-SVX07J-EN