Ac Chopper - Hitachi Utopia RPI-2.5HRG Service Manual

3.2

AC Chopper

Reduction of Electromagnetic Sound
Fan Motor Control by AC Chopper:
Lower electromagnetic sound and vibration have been achieved by AC Chopper control than thyristor
control.
AC Chopper Control
Concept of Fan Speed Control
The voltage applied to the fan motor is controlled by chopping
(ON/OFF) the power supply voltage at a frequency of 20kHz.
Features
• Sinusoidal Wave Pattern and Remarkable Low Level of Electromagnetic Sound
• No Generation of Harmonic Current
(1) Specifications
Rated Current of AC Chopper
Applicable Power Source
Output Voltage
Output Current (Maximum)
Control Method
Chopping Frequency
Input Duty Signal
Accuracy of Output Voltage
Output/Characteristics
Soft Start
Overcurrent Protection Method
Overcurrent Setting (Minimum)
Overcurrent Protection Area
Output Current (A)
(Max. x 2)
(Max. )
0 10
2.1A
Single Phase 220/240V + 10% 50/60Hz
2.1A
100kHz + 5% Current 2 to 8mA + 10%
Output Duty (%)
100
0 10
2.1A
: Protection Area
Input Duty (%)
30 50
Single Phase 220/240V + 10%
AC Chopper Control
20kHz + 20%
+ 6%
b
d
50
Input Duty (%)
Input Duty: 10%/s
Current Limiter
[For 5.6A]
Output Current (A)
50Hz
60Hz
4A
3.5A
0 10 30
MAIN PARTS
5.6A
5.6A
Input Duty = b/a
a
Output Duty = d/c
c
5.6A
: Protection Area
4.75
Input Duty (%)
40 50
3-3