Economizer Actuator; Variable Frequency Drive - Carrier 48FP Controls Operation And Troubleshooting

Table 63 — Actuator Degrees of Travel and DIP Switch Settings
ACTUATOR
Economizer
Inlet Guide Vanes (034-074)
Modulating Power Exhaust

Economizer Actuator

OPERATION — The motor feedback potentiometer and con-
trol current input circuit form a bridge circuit. As long as the fi-
nal control element remains at the position proportional to the
input current from the controller, the circuit is balanced, and the
motor does not run. When the value of the controlled medium
changes, the current from the controller changes, and unbal-
ance is amplified to energize the triac switching to run the mo-
tor in the proper direction to correct the change in the tempera-
ture or the pressure. The motor turns the feedback potentiome-
ter to rebalance the circuit and stop the motor.
CHECKOUT — After installation and linkage adjustment,
operate the motor through the controller. Make sure that:
• The motor operates the dampers properly.
• The motor responds properly as the input is varied.
• The auxiliary switch, if used, operates at the desired point
of motor rotation.
Inspect the motor, linkage, and damper to see that all me-
chanical connections are correct and secure. In damper installa-
tions, the pushrod should not extend more than a few inches
past the ball joints. Check to see that there is adequate clear-
ance for the linkage to move through its stroke without binding
or striking other objects. See controller or system instructions
for additional checkout procedures.
Motor Operation Checkout (Fig. 48) — Check motor opera-
tion as follows:
1. To close the motor, open terminals +, –, and F.
2. To open the motor, connect terminal F to either the
positive (+) or negative (–) motor terminal.
Variable Frequency Drive (VFD) (Unit Serial
Numbers 0779F or later)
Factory-option VFD is located near the supply fan and
motor. During any service work or programming at the
VFD, operation of the fan and motor is not desirable.
Either disable the supply fan or install the accessory VFD
remote display package.
NOTE: Following section refers to factory-installed option
VFDs. The VFD model number is TOSVERT130-E3. These
VFDs are specially modified for use on Carrier equipment.
Some specifications and control configuration defaults for
Carrier applications will differ from standard ''E3'' product
manual information supplied with unit. See Appendix E for
listing of Carrier-specific default values.
STANDARD VFD CONTROL — On 48FP,JP and 50FB,
FP,JB,JP units with factory-installed option VFD, the VFD
controls duct pressure (DP) in response to input signals
received form the base unit PIC control module. The base unit
control monitors duct pressure via a differential duct pressure
transducer. The pressure transducer is located in the unit auxil-
iary control box (see Fig. 32 and 33). The pressure transducer's
low pressure reference port is routed to the outside of the unit
DEGREES OF TRAVEL
110
45
70
84
DIP SWITCH(ES)
OPEN
8 and 10
6 and 10
5 and 10
_ _ _
+
F
ELECTRONIC
CIRCUIT
TRIAC
TRIAC
SWITCHING
SWITCHING
FEEDBACK
POTENTIOMETER
CLOSED OPEN
LIMIT LIMIT
CW
CW
WINDING
WINDING
(OPEN)
(CLOSED)
(SEE NOTE)
(SEE NOTE)
NOTE: Direction of motor travel as viewed from power end.
Fig. 48 — Economizer Actuator
cabinet by a factory-installed tubing section. The pressure
transducer's high pressure reference point must be field-routed
to the duct pressure pick-up which is field-supplied and
installed in the supply duct. See Air Pressure Tubing page 40
for recommended location.
The DP transducer monitors the static pressure in the supply
duct and provides a 2 to 10 vdc signal to the base unit control
module (PSIO1, Channel 11). Refer to Table 64 for transducer
output signal characteristics (static pressure vs. signal volts).
The base unit control module compares this signal representing
actual duct pressure to the user-configured DP set point and
then signals required changes in VFD output to the VFD (via 4
to 20 mA signal at PSIO1 Channel 16). The VFD then adjusts
its output to the supply-fan motor to maintain the desired DP
set point. When operating with the factory-standard PIC con-
trols, the VFD's internal PID logic feature is disabled.
SUPPLY FAN MOTOR OVERLOAD PROTECTION —
The VFD also provides operating overload protection for the
supply-fan motor. The VFD's overload function matches the
factory-installed motor (motor size and efficiency). If the sup-
ply-fan motor is changed from the original factory selection,
the overload value may need to be changed by the service per-
son. Contact your local Carrier representative for assistance in
determining the proper overload setting.
NOTE: VFD size is matched to factory-installed motor size.
Do not increase motor size without also changing to an equiva-
lent VFD size.
DIP SWITCHES
CLOSED
All Others
All Others
All Others
T2
RED
BRAKE
CIRCUITRY
T BLK