Carrier WeatherMaster 48HC04 Service And Maintenance Instructions page 5

design, the electronic circuitry is integral to the motor assembly
and cannot be serviced or replaced separately.
The 208/230-v units use a 230-v motor. 460-v units use a 230-v
motor with a stepdown transformer (mounted on the end of the fan
housing, see Fig. 5). 575-v units use a 460-v motor with an auto-
transformer. 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.
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 pro-
vide a different motor torque output. See Table 1. Factory default
tap selection is Position 1 for lowest torque/speed operation.
460, 575-v Units
208/230-v Units
Fig. 7 — Direct-Drive Supply Fan Assembly
5
Table 1 — Motor Tap Programing (Percent of
Full-Load Torque)
48HC
TAP 1 TAP 2
UNIT SIZE
32 38
04
46 58
05
73 82
06
NOTE: Factory Default: Tap 1 (VIO)
Selecting another speed:
1. Disconnect main power to the unit. Apply lockout/tag-out
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.
TAP 3 TAP 4 TAP 5
45 50 100
61 69 100
85 90 100