Built-In Electronic Protections (Within The Module/Inverter); Compressor Start-Up; Overload Detection And Protection; Power Limitation (Temperature Protection) - Fisher & Paykel 790 Active Smart Service Manual

6.1.5.2

Built-in Electronic Protections (Within the Module/Inverter)

6.1.5.2.1

Compressor Start-up

In case any anomaly occurs during compressor starting, the control will wait 6 seconds before repeating the
start-up. If the compressor doesn't start after 12 trials, the control will wait 8 minutes before repeating the
start-up procedure (this condition may be when pressures are not equalised between suction and discharge
sides in the refrigeration system, eg; after an interruption in the mains supply).
6.1.5.2.2

Overload Detection and Protection

The control can detect an overload condition by monitoring the current consumed by the compressor. If
overload is detected the control reduces the current by reducing the speed of the compressor until the
overload disappears, when the speed will return to the required value.
If the overload increases, the control will continue to decrease the current until the minimum speed of 1590
rpm may be reached, at which point the compressor may "stall", and the control will return to the start-up
procedure.
6.1.5.2.3

Power Limitation (Temperature Protection)

The control limits the power supplied to the compressor to 200 watts to keep all electrical components below
a safe operating limit. The power is limited in the same way as the current in the overload protection.
6.1.5.2.4

Short Circuit Protection

In a case where a short circuit occurs, (eg; motor winding damage, connection faults etc), the same current
limiting control is actuated to reduce further damage. In the case of a major failure, a fuse within the inverter
will break the current supplied to the control. This fuse cannot be replaced in servicing.
6.1.5.3

VCC Module/Inverter Identification

The module/inverter has an identification label giving the following information:
Inverter Version
Frequency:
50 – 60 Hz
6.1.5.4

Fault Finding

6.1.5.4.1

High Voltage Power Supply Circuit

Whenever power is supplied to the refrigerator, there should always be 110V mains voltage in the high
voltage harness between the power/control module and the VCC module/inverter. This can be checked by
removing the rear cover of the VCC module/inverter and testing with a multimeter. There should be 110V
across the spade terminals above the edge connector at the top of the module (refer Photo 6.1.5.4). If this is
not present, check the continuity of the harness from the power/control module. If there is continuity through
the harness, replace the power/control module.
6.1.5.4.2

Signal Circuit

With a multimeter that can measure frequency, the signal circuit between the power/control module and the
VCC module/inverter can be checked. Remove the rear cover of the VCC module/inverter and connect the
multimeter across the two pins beside the signal harness edge connector. When the compressor is meant to
be running, the frequency should be between 53Hz and 150Hz. At start up the frequency will be 75Hz for
2.5 seconds, then 53Hz for 27 seconds before changing to 150Hz. Multiplying the frequency of the signal
circuit by 30 will give the compressor speed, so if the frequency is 53Hz the compressor speed will be
1590rpm, and if it is 150Hz the compressor speed will be 4500rpm.
Voltage:
11 = 115-127V
24 = 220-240V
VCC3 11 56
A = Stand alone version box
F = Attached version box
Electronic board version
XX A XX
Cable configeration
23