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8.
C
8-1. Current Control
The operating current may rise as a result of causes
including increasing heating or cooling loads or
decreases in power voltage. In these cases, the
operating frequency is automatically reduced, or
operation is stopped, in order to control the operating
current so that it is 20 A or less.
As a result:
• Power breakers and fuses will not be tripped.
• Operation can continue during this period with
somewhat reduced heating or cooling capacity.
• Operation at normal capacity is restored when the
cause of the current rise is eliminated.
e
r t on o un t on
a
le o o erat on or ool n
22. A
1 .0A
12. A
Target
frequency
requency
• Operates at the target frequency at Point A and below.
• tops increases to the frequency between Points A and .
• educes the frequency by 1 Hz per 0. seconds when Point is e ceeded.
• tops operation, and restarts it appro imately minutes later, if Point C is
e ceeded.
ay operate when sudden voltage fluctuations occur.
8-1-1. Auto at
The operating frequency is reduced automatically, or
operation is stopped, in order to control the operating
current so that it is at or below the values shown in the
table below.
Point C peak cut trip
Point
Hz reduction
Point A Hz increase prohibit
8-1- . Current ontrol
The operating frequency upper limits shown in the figure
below are established for frequency reduction and
increase prohibit.
a
le o o erat on ur n
Current (A)
Trip
Hz reduction
Hz increase
prohibit
.
.1
0
0
S
tops operation
Appro . minutes
Indicates trouble.
requen y ontrol
0A
C
L
22.
1 .0
12.
ool n
Hz reduction
Hz increase prohibit
Hz reduction
Hz increase prohibit
requen y (Hz)
8- . Low Start Current
Operation starts at 10 Hz, and the start current is less than
the normal operating current. This prevents the flickering of
fluorescent lights or television screens that occurs when
ordinary A/C units start.
8- . Co
To protect the compressor coil from overheating, the
operating frequency is controlled based on the compressor
discharge temperature.
12
Power Point C
10
Point
Point A
100
ithin the increase prohibit range, the range changes
to the Hz reduction range 2 Hz every 0 seconds if
the compressor temperature rises by 2 C.
8- .
8- -1. C
29 C
22
re
or e
( C)
Trip
Hz every 0 sec. reduction
2Hz every 0 sec. reduction
o control
ut oor an Control
L o erat on
an H
1 C
aintain previous status
an
ess than
Hz
requen y
erature Control
Increase
prohibit range
Hz reduction
an H
an H
an H
Hz
Hz or above
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