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15. VARIABLE SPEED CoMPRESSoR
15.1. CoMPoNENt FoR tHE VARIABLE SPEED DRIVE
15.1.1. FILtER
the filter in the compressor driver box (lF on the wiring diagram) situated under the top panel is used to remove
the noise on the power line generated by the power conversion circuit.
15.1.2. DRIVER
the driver Pcb is in the driver box (cd on the wiring diagram). the driver converts the 230Vac to dc then powers
the three coils on the compressor through high speed semiconductor switching devices. the driver is able to detect
the actual compressor rotation as well as the voltage and current. the driver can detect certain types of malfunction
and will stop the compressor.
Faults detected by the driver
over voltage
detected on the ac or dc lines
under voltage
detected on the ac or dc lines
over current
the compressor current use exceeds the maximum current
overheating
internal components temperature too high.
synchronisation
the compressor does not rotate at the expected speed or has not started.
component
Power component failure
some of the above alarms are triggered then reset rapidly by the driver. in some cases the alarm is not memorised
by the main controller but an unusual compressor stop is detected. in this case an alarm e53 is shown. this allows
the compressor to restart using the correct starting sequence. if the alarm e53 is repeated a lockout occurs requiring
manual reset.
an occasional alarm is not considered as important but a lockout alarm requires further investigation into its root
cause.
repeated alarms detected by the driver and resulting in a driver lockout need to be reset by switching off the power.
15.1.3. CoMPRESSoR
the compressor is a special inverter version with a dc motor.
15.1.4. MAIN CoNtRoLLER
the main controller communicates via a front mounted communication card with the driver.
the compressor speed is set by the main controller. in the event of a communication failure between the main
controller and the driver the compressor will stop.
15.2. CoMPRESSoR StARtING SEqUENCE
every time the compressor starts except for a deice cycle the following sequence is followed:
1.
outdoor fans will turn on for 3 minutes or must have been on during the last 30minutes. this is to
be sure that the outdoor air temperature value used is precise.
2.
the electronic expansion valve (eeV) opens.
3.
the compressor will start and accelerates to 50hz.
4.
the eeV will open to a pre-defined position and adjusts its position automatically after 15s.
5.
the compressor remains at 50hz for 3 minutes. after this time the compressor speed will change
automatically according to the water temperature and water setpoint.
