Supply Fan (Blower) Section; Supply Fan (Direct-Drive); Ecm Motor - Carrier WeatherMaster 50HCQ04-12 Service And Maintenance Instructions

Re-install the Manual Outside Air Hood Screen by placing the
screen frame in its track, rotating the retainer back down.
Tighten all screws..

SUPPLY FAN (BLOWER) SECTION

WARNING
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal inju-
ry or death.
Before performing service or maintenance operations on
the fan system, disconnect all electrical power to the unit
and apply approved Lock-out/Tagout procedures to the unit
disconnect switch. Do not reach into the fan section with
power applied to unit. Electrical shock and rotating equip-
ment could cause severe injury.

Supply Fan (Direct-Drive)

For unit sizes 04, 05 and 06, a direct-drive forward-curved cen-
trifugal blower wheel is an available option. The motor has
taps to provide the servicer with the selection of one of five
motor torque/speed ranges to best match wheel performance
with attached duct system. See Fig. 5 and Fig. 6.
Motor Plug Position
(95° from vertical)

ECM Motor

Fig. 5 — 50HCQ Direct-Drive Supply Fan Assembly
Gnd
GRN/YEL
L1
BLU
C L G N
Com
BRN
1 2 3 4 5
Speed
Taps
Fig. 6 — ECM Motor Connectors
95°
ECM Power
Transformer
(460, 575v)
L2
YEL
Motor
Power
Connections
VIO
Default Connection
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 mo-
tor, 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 sig-
nal to one of the five motor communications terminals. When
the 24V signal is removed, the motor will stop. The motor con-
trol 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 main-
tain 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 pro-
vide a different motor torque output. See Table 1. Factory default
tap selection is Position 1 for lowest torque/speed operation.
Table 1 — 50HCQ Motor Tap Programing
(percent of full-load torque)
UNIT SIZE TAP 1
04 29
05 46
06 49
Factory Default: Tap 1 (VIO)
SELECTING ANOTHER SPEED:
1. Disconnect main power to the unit. Apply 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 (ter-
minals 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.
5
TAP 2 TAP 3 TAP 4
33 41 48
49 57 67
55 79 90
TAP 5
100
100
100