REYMSA COOLING TOWERS, INC.
www.reymsa.com
58
C.1.2 CONFIGURATION AND START-UP FOR ABB ACH550-UH
REYMSA recommends the next connection diagram for ABB ACH550-UH:
Start-Stop Methods
Soft-start is the prefered method for start-stop
fan motor by means of 30 seconds acceleration
and deceleration ramp.
Acceleration time is the time required of output
frequency from 0 Hz to 60 Hz maximum frequency.
Deceleration time is from a frequency decrease
to 0 Hz.
Operation Method
The VFD motor will be modulated from minimum to
maximum speed based on the output from a PID
loop.
VFD shall remain ON as long as there is a
difference in temperature between the set point
and the actual temperature.
212°F
RANGE RTD
TEMPERATURE
32°F
VFD ON
@ MIN FREQ
ACTUAL TEMP
SP
20%
Figure C-4: Measuring range RTD.
FREC.
MAX FREQ
30 s ACELERATION TIME
30 s DECELERATION TIME
MIN FREQ
0 Hz.
Figure C-2: Start-stop method.
SP
ERROR
ACTUAL
TEMP.
PID MOTOR
SENSOR
Figure C-3: Operation method.
VFD
1 SCR
2 AI1
3 AGND
4 10V
5 AI2
6 AGND
7 AO1
8 AO2
9 AGND
10 24V
11 GND
12 DCOM
13 DI1
14 DI2
15 DI3
16 DI4
17 DI5
18 DI6
SW
-
+
BRIDGE
BRIDGE
START
BRIDGE
SIGNAL
4-20 mA
0-10 V
VIBRATION SWITCH
BRIDGE
BRIDGE
RTD
Figure C-5: Recommended Connection Diagram for ABB ACH550-UH.
Operation
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