Daikin's 2YC63AXD compressor electric resistance?

[basti]

Hello!

I have Daikin inverter swing compressor model 2YC63AXD. I measured 0.6 ohm between terminals (U-V-W). Could this be right??. Meter itself has 0.1 ohms and i think it isn't broken (Meter model is Appa 30R DC/AC Clampmeter).

(Outdoor split unit type is Daikin RZP71DV1, one phase , 230VAC/50Hz)


Basti.

[Brian_UK]

Hi Basti and welcome to the forum.

I do not know the design resistance of this compressor but being a single phase unit I would expect the readings to be different.

The start and run windings should give different resistances.

[The Viking]

Moi,

It could well be right, remember that this inverted unit really has a 3 phase compressor, even thou you only got a single phase supply to the unit.

The important checks are:
(Before you do this, disconnect the leads from the compressor!!)
1. Is the compressor down to earth (can you get resistance between U/V/W and the pipe work, preferable measured with a megger?)

2. Does the inverter supply even voltage between the phases? (Start the unit with the compressor disconnected, measure the voltage from each phase to neutral, it doesn't matter what voltage you get as long as it's the same for all 3)



BTW, Why are you asking? Is there a fault code flagged up?

HINT:
If you haven't got a megger, use a lamp on a lead.
To do this, disconnect the lead to the compressor then attach the lamp's neutral to the compressor terminal and the lamp's phase to the power supply, if it lights up the compressor is U/S.....

[basti]

Hi Basti and welcome to the forum.

I do not know the design resistance of this compressor but being a single phase unit I would expect the readings to be different.

The start and run windings should give different resistances.

Thank's for the reply!. As i mentioned, unit is single phase but compressor is three phase DC-inverter (550VDC I'll think) with neutral line. So i ask has anyone engineer measured same compressor electric resistance ?

I ask this because inverter PCB board is broken. (Blow's main fuse)

[basti]

Moi,

It could well be right, remember that this inverted unit really has a 3 phase compressor, even thou you only got a single phase supply to the unit.

The important checks are:
(Before you do this, disconnect the leads from the compressor!!)
1. Is the compressor down to earth (can you get resistance between U/V/W and the pipe work, preferable measured with a megger?)

2. Does the inverter supply even voltage between the phases? (Start the unit with the compressor disconnected, measure the voltage from each phase to neutral, it doesn't matter what voltage you get as long as it's the same for all 3).

BTW, Why are you asking? Is there a fault code flagged up?

HINT:
If you haven't got a megger, use a lamp on a lead.
To do this, disconnect the lead to the compressor then attach the lamp's neutral to the compressor terminal and the lamp's phase to the power supply, if it lights up the compressor is U/S.....

1) No it's not down the earth. Meter shows 'infinity' ohms.
2) I'll tried without connected compressor and dc-fan. Still blows house's main fuse.

No, there is no fault code on remote controller.
I've tried the clarify what broke the inverter board, is the compressor small resistance guilty of this?. Maybe i put new inverter pcb board in to unit and hope the best!

[Redhot]

Hi basti
The resistance between the windings I would expect to be ok from a similar model which was 0.8 ohms the question is what caused the PCB to fail from experiance the most likely cause the compressor. So as the viking suggested test the compressors insulation resistance to earth but, also it is possible that the compressor is siezed and you wont find out until you put in a new PCB and possibly damage that if that is the case. Therefor suggest replacing PCB and compressor this became Daikins policy on a particular building with a simular outdoor unit as mentioned above. Not to sure if the model you have has two capacitors but worth testing WARNING discharge with a resistor as they can be around 2000 microfarads!

Cheers
Redhot

[The Viking]

1) No it's not down the earth. Meter shows 'infinity' ohms.
2) I'll tried without connected compressor and dc-fan. Still blows house's main fuse.

No, there is no fault code on remote controller.
I've tried the clarify what broke the inverter board, is the compressor small resistance guilty of this?. Maybe i put new inverter pcb board in to unit and hope the best!

So, when you say that the meeter shows "infinity" Ohms, what meeter did you use?
Generally, a standard clamp meeter is not good enough to test insulation (if a compressor is down to earth). A megger will spike the tested component with a high voltage (typically 500-1000 Volt), therefore they will show resistance where a normal "Ohm" meeter will see an open circuit.
See my previous hint if you haven't got access to a megger. (It might be rough but it will test your compressor at it's normal running voltage).

Does it blow the main fuse straight away or does it last until the unit tries to start the compressor?

If it goes straight away, you are most likely looking at something on the primary side of the inverter, like the noise filter. Remember, the inverter consists of many components which can be tested individually.

Seized compressor? I wouldn't have thought that this would blow the inverter board or even the fuse, normally this would flag up an L9 error.

:cool:

[The Viking]

Maybe i put new inverter pcb board in to unit and hope the best!

Destructive fault-finding?

I like it, you're my type of engineer!;)


:cool:

[Brian_UK]

Apologies all, just reread the original post and, of course, my answer does not apply.:o

Please ignore and I will go and sleep quietly in the corner;)

[philjd26]

Destructive fault-finding?

I like it, you're my type of engineer!;)


:cool:
ha ha ha:D

[The Viking]

Basti,

If you aren't sure, fit a new inverter but instead of wiring it up to the compressor, let it run another 3 phase motor that you know to be good (pump, fan or whatever), it shouldn't matter if the motor you use is smaller than the compressor and if it's bigger then the only thing that should happen is that error code "E5" should flag up.
Then you would know that the controls and the inverter are OK.

The compressor you can run (momentarily) from any 3 phase supply, if you got any on site, just be careful with the phase rotation)
If you haven't got 3 phase available then it might be worth trying to fit some fuses in-line between the inverter and the compressor?

You don't really want to blow a new inverter board up, do you?

[basti]

Basti,

If you aren't sure, fit a new inverter but instead of wiring it up to the compressor, let it run another 3 phase motor that you know to be good (pump, fan or whatever), it shouldn't matter if the motor you use is smaller than the compressor and if it's bigger then the only thing that should happen is that error code "E5" should flag up.
Then you would know that the controls and the inverter are OK.

The compressor you can run (momentarily) from any 3 phase supply, if you got any on site, just be careful with the phase rotation)
If you haven't got 3 phase available then it might be worth trying to fit some fuses in-line between the inverter and the compressor?

You don't really want to blow a new inverter board up, do you?

Thank's for the reply!

I buy new compressor and install it with new inverter board for sure. I give to look the inverter board to my friend and he said that some power transistor in pcb has been run very hot and he show me the 'hot spots' in soldering.

[basti]

A megger will spike the tested component with a high voltage (typically 500-1000 Volt), therefore they will show resistance where a normal "Ohm" meeter will see an open circuit.

:cool:

Ok! I have insulation test meter. I if test compressor meters 500VDC settings so what readings i should expect?

[The Viking]

Still open circuit, you don't want anything between the terminals and earth, if there is then the compressor is gone.

[basti]

I inspect the old inverter pcb and compared with new one. I found that both rectifiers one side has short circuit. (I measured Fluke's diode test and it show 0.488vdc with new board and old one 0 vdc.)