Carrier 50TCQ 04 Series Service And Maintenance Instructions page 6

ECM Motor — The direct−drive motor is an X13
Electronically Commutated Motor (ECM). An ECM
motor contains electronic circuitry used to convert
single−phase line AC voltage into 3−phase DC voltage to
power the motor circuit. The motor circuit is a DC
brushless design with a permanent magnet rotor. On the
X13 ECM Motor design, the electronic circuitry is
integral to the motor assembly and cannot be serviced or
replaced separately.
208/230V units use a 230V motor, 460V units use a 460V
motor and 575V units use a 460V motor with an
autotransformer. Motor power voltage is connected to
motor terminals L and N (see Fig. 6 and Fig. 7); ground
is connected at terminal G. The motor power voltage is
ALWAYS present; it is not switched off by a motor
contactor.
Motor operation is initiated by the presence of a 24V
control signal to one of the five motor communications
terminals. When the 24V signal is removed, the motor
will stop. The motor control signal is switched by the
defrost board's IFO output.
Evaluating motor speed — The X13 ECM Motor uses a
constant torque motor design. The motor speed is adjusted
by the motor control circuitry to maintain the programmed
shaft torque. Consequently there is no specific speed value
assigned to each control tap setting. At the Position 5 tap,
the motor speed is approximately 1050 RPM (17.5 r/s) but
varies depending on fan wheel loading.
Selecting speed tap — The five communication terminals
are each programmed to provide a different motor torque
output. See Table 1. Factory default tap selection is
Position 1 for lowest torque/speed operation.
Table 1 – 50TCQ Motor Tap Programing (percent of
full−load torque)
Unit Size Tap 1 Tap 2
04 29 33
05 46 49
06 49 55
Factory Default: Tap 1 (VIO)
Selecting another speed:
1. Disconnect main power
lockout/tagout procedures.
2. Remove the default motor signal lead (VIO) from
terminal 1 at the motor communications terminal.
3. Reconnect the motor signal lead to the desired speed
(terminals 1 through 5).
4. Connect main power to the unit.
Motor "rocking" on start−up — When the motor first
starts, the rotor (and attached wheel) will "rock" back and
forth as the motor tests for rotational direction. Once the
correct rotational direction is determined by the motor
circuitry, the motor will ramp up to the specified speed.
The "rocking" is a normal operating characteristic of
ECM motors.
Troubleshooting the ECM motor — Troubleshooting the
Tap 3 Tap 4 Tap 5
41 48 100
57 67 100
79 90 100
to the unit. Apply
X13 ECM requires a voltmeter.
1. Disconnect main power to the unit.
2. Remove the motor power plug (including the control
BRN lead) and VIO control signal lead at the motor
terminals.
3. Restore main unit power.
4. Check for proper line voltage at motor power leads
BLK (at L terminal) and YEL (at N terminal).
Table 2 – Motor Test Volts
Unit Voltage Motor Voltage
208/230
460
575
5. Using a jumper wire from unit control terminals R to
G, engage motor operation. Check for 24v output at
the defrost board terminal IFO.
6. Check for proper control signal voltages of 22V to
28V at motor signal leads VIO and BRN.
7. Disconnect unit main power. Apply lockout/tagout
procedures.
8. Reconnect motor power and control signal leads at
the motor terminals.
9. Restore unit main power.
10. The motor should start and run. If the motor does not
start, remove the motor assembly. Replace the motor
with one having the same part number. Do not
substitute with an alternate design motor as the
torque/ speed programming will not be the same as
that on an original factory motor.
Replacing the X−13 ECM Motor — Before removing
the ECM belly−band mounting ring from old motor:
1. Measure the distance from base of the motor shaft to
the edge of the mounting ring.
2. Remove the motor mounting band and transfer it to
the replacement motor.
3. Position the mounting band at the same distance that
was measured in Step 1.
4. Hand−tighten mounting bolt only. Do not tighten
securely at this time.
5. Insert the motor shaft into the fan wheel hub.
6. Securely tighten the three motor mount arms to the
support cushions and torque the arm mounting screws
to 60 in−lbs (6.8 Nm).
7. Center the fan wheel in the fan housing. Tighten the
fan wheel hub setscrew and torque to 120 in−lbs (13.6
Nm).
8. Ensure the motor terminals are located at a position
below the 3 o'clock position. See Fig. 5. Tighten the
motor belly−band bolt and torque to 80 in−lbs (9.0
Nm).
Supply Fan (Belt−Drive)
The belt−drive supply fan system consists of a
forward−curved centrifugal blower wheel on a solid shaft
with two concentric type bearings, one on each side of the
blower housing. A fixed−pitch driven pulley is attached to
6
Min-Max Volts
230 187-253
460 414-506
460 414-506