Toshiba MM-A0160HX, Service Manual, Page: 38 / 135

39
11
Outline of Control
Outdoor Units
Item Operation explanation and applied data, etc. Remarks
11. IPDU (Inverter)
control
IPDU controls the inverter compressor by command
frequency, frequency up/down speed, and current
release control value from the interface P.C. board.
The main controls of IPDU control P.C. board are
described below.
(1) Current release control
The output frequency is controlled by AC input
current value which is detected by T02 on the
control P.C. board, to prevent the inverter input
current dropping lower than the specified value.
A zone : The normal operation is executed.
D zone : The present operation frequency is kept.
B zone : The operation frequency is decreased.
C zone : Decrease of the operation frequency
stopped, and the present operation
frequency is kept.
(2) Heat sink temp. detection control
1) The heat sink temp. is detected by the thermistor
in the compressor driving module Q200, and
the inverter compressor driver stops when
120°C is detected.
2) When the inverter compressor driver stops, 1 is
counted to the error count. If the error count
reaches 3 the system generates a fault code and
system operation stops.
NOTE:
When the error has been determined, the ambient
outdoor temp. or an outdoor fan error is considered.
(3) Over-current protective control
1) The compressor stops when T03 on IPDU control
P.C. board detects over-current.
2) When the compressor stops, 1 is counted to the
error count, and the compressor reactivates after
2 minutes 30 seconds. After reactivation, the
error count is cleared if the operation continues
for 10 minutes or more.
(4) High pressure SW control
1) The compressor driver stops when the inverter
compressor high pressure SW operates.
2) When the compressor driver stops, 1 is counted
to the error count, and the compressor driver
reactivates after 2 minutes 30 seconds. After
reactivation, the error count is cleared if the
operation continues for 10 minutes or more.
Current value
(22A) I
1
(21.5A) I
2
A zone
B zone
D zone C zone