Toshiba Inverter compressor resistance

[eskimo2]

I came across a Toshiba RAS3M26YAV-E with a burnt IPDU pcb. (single phase input)

does any one know what the winding resistances of the compressor should be. They measured out at 0.25-0.3 ohm across any two of the three pins.

This seems some what low to me as compared to a standard 3 or 4hp compressor?

anyone know the resistance should be?
Alos if it is low...WHY?
also one toshiba file says compressor insulation should be <10Mohm, while a different file says it should be "open circuit" ... infinity i think they mean....the comp in question was at 40Mohm

[nike123]

I came across a Toshiba RAS3M26YAV-E with a burnt IPDU pcb. (single phase input)

does any one know what the winding resistances of the compressor should be. They measured out at 0.25-0.3 ohm across any two of the three pins.

This seems some what low to me as compared to a standard 3 or 4hp compressor?

anyone know the resistance should be?
Alos if it is low...WHY?
also one toshiba file says compressor insulation should be <10Mohm, while a different file says it should be "open circuit" ... infinity i think they mean....the comp in question was at 40Mohm


Compressor winding resistance depend on used wire for windings, windings temperature and winding configuration.
For measuring that you need to have mili-ohm meter and not universal DMM. Also you need to know at what temperature is what resistance expected.
For field evaluation of winding condition it is sufficient to check if there is no difference in measured resistance of all 3 windings and that no winding has "infinity" resistance. You could do that with good DMM. Also, at field, you need to measure compressor winding insulation.

Insulation should be at least 1 megaohm plus 1000 ohm per 1 volt of power supply voltage (IEEE 43). Below that you should discard that compressor. It must be measured with megaohm tester at corect (500V) test voltage. Measuring of insulation with DMM which have 9V battery is not right because that is insulation resistance at 9V and compressor work with much higher voltage. Therefore it is essential to measure insulation with correct voltage.

Check this PDF:
http://www.mediafire.com/?11izldhsd3d

[eskimo2]

At 0.25ohm or 0.3 ohm resistance, + or - 40 C from whatever it was aint going to make a lot of difference to that what I actually measured....if I was measuring a high resistance then yes I would (might) need to know the temperature....but not for checking the approximate resistance of a motor windings

The measurement I recorded just seem very low.... almost a dead short (ie no resistance)?

[nike123]

At 0.25ohm or 0.3 ohm resistance, + or - 40 C from whatever it was aint going to make a lot of difference to that what I actually measured....if I was measuring a high resistance then yes I would (might) need to know the temperature....but not for checking the approximate resistance of a motor windings

The measurement I recorded just seem very low.... almost a dead short (ie no resistance)?

Resistance of windings of 3-phase Danfoss scroll compressor of 14 kW refrigeration capacity (at -10/40°C wit R407C) (SZ120-6) is 0,35 Ohm at 20°C! Your resistance looks to me pretty OK.