How do I know if my ohm readings on fan and compressor mean good?

webejamin_1982 · 11-19-2009, 11:11 PM

Ok I have a condenser fan motor that ohms out at: Re-Br - 68.2 ohms
Bla-Br - 49.5 ohms
Bla-Re - 19.0 ohms
I also have a compressor that ohms out at: Run-Cap - 0.8 ohms
Cap-Start - 2.2 ohms
Start-Run - 3.2 ohms
So are those good numbers and how can you tell that from taht?
Also everything else is good Just put new contactor in. It is getting 24 volts to coil, but one question I do have is. The way i read it from main power souce was that it was supose to get 208-240 main but on one leg when I read it from line too ac case oot was 120 but the other line only read 14 would I have a breaker blown internally? I hope that makes some sence. Thanks for your time and help either way.

Houston204 · 11-20-2009, 01:09 AM

Your readings look okay to me. You are calling common "cap" though.
Try turning off the breaker completely, then turning it back on before condemning the breaker. Measure across L1 to L2 for 240VAC.
Do you have an Ampere meter?

webejamin_1982 · 11-20-2009, 12:21 PM

Would that work? Also thanks for the ohm advice. So through volts ac from line one two line two form main power sourse through meter I should read 240, right? I have fliped breaker a couple times but have not looked at the breaker internally itself yet, or just to see if I could see melting or any noticable signs yet. Any other advice would be much apreciated if you have any time. I do understand you could and should be getting paid for this. I also thank you for that fact of you helping em to be able to do it right. Also let em add too start the hole thing off I replaced run cap it was blown out and the contacts on the contactor where blown out that is also why I thought I should check breaker but have not yet done that just a thought that popped up and wont be going back out to the a/c untill monday. So if in senerios you would be able to go through that I might want to look at would be greatfull also. THanks again.

Houston204 · 11-20-2009, 06:21 PM

That is a good meter. I used Fieldpiece for almost 20 years and I like them. I have one that looks like that.

Do you have 240VAC at the breaker?
If you have a SquareD breaker type disconnect out by the condenser, that's probably the problem. Check for 240vac to it and 240vac from it.

Turn off the breaker and Ohm T1 and T2 to ground. If it shows to have a short, start isolating individual wires. I don't think it is the motor or compressor but it could still be the wires to them or your crankace heater.

webejamin_1982 · 11-21-2009, 11:39 AM

I will not be going out there till monday, but where I got the volts was from the saftey breker by condenser. So you say pull out fuse pin block and ohm each leg to ground. If good it should read a resistance and if bad it will be over load right? Also how would I check crankcase heater. Also like I said I have not checked the breaker pannel inside itself to see If I am having power problems there. I have flipped the on and off a few times but have not checked the internal structure or noticable flaws in the breaker switch itself. Thanks again.

**beenthere** · 11-21-2009, 03:22 PM

Did you check the breaker in the main panel box.

11-19-2009, 11:11 PM	#1
webejamin_1982 Newbie Join Date: Nov 2009 Posts: 7	How do I know if my ohm readings on fan and compressor mean good? Ok I have a condenser fan motor that ohms out at: Re-Br - 68.2 ohms Bla-Br - 49.5 ohms Bla-Re - 19.0 ohms I also have a compressor that ohms out at: Run-Cap - 0.8 ohms Cap-Start - 2.2 ohms Start-Run - 3.2 ohms So are those good numbers and how can you tell that from taht? Also everything else is good Just put new contactor in. It is getting 24 volts to coil, but one question I do have is. The way i read it from main power souce was that it was supose to get 208-240 main but on one leg when I read it from line too ac case oot was 120 but the other line only read 14 would I have a breaker blown internally? I hope that makes some sence. Thanks for your time and help either way.

11-20-2009, 01:09 AM	#2
Houston204 Member Join Date: Oct 2009 Location: Texas Posts: 581	How do I know if my ohm readings on fan and compressor mean good? Your readings look okay to me. You are calling common "cap" though. Try turning off the breaker completely, then turning it back on before condemning the breaker. Measure across L1 to L2 for 240VAC. Do you have an Ampere meter?

11-20-2009, 12:21 PM	#3
webejamin_1982 Newbie Join Date: Nov 2009 Posts: 7	How do I know if my ohm readings on fan and compressor mean good? Would that work? Also thanks for the ohm advice. So through volts ac from line one two line two form main power sourse through meter I should read 240, right? I have fliped breaker a couple times but have not looked at the breaker internally itself yet, or just to see if I could see melting or any noticable signs yet. Any other advice would be much apreciated if you have any time. I do understand you could and should be getting paid for this. I also thank you for that fact of you helping em to be able to do it right. Also let em add too start the hole thing off I replaced run cap it was blown out and the contacts on the contactor where blown out that is also why I thought I should check breaker but have not yet done that just a thought that popped up and wont be going back out to the a/c untill monday. So if in senerios you would be able to go through that I might want to look at would be greatfull also. THanks again. Last edited by webejamin_1982; 11-20-2009 at 12:26 PM. Reason: Needed too add more detail.

11-20-2009, 06:21 PM	#4
Houston204 Member Join Date: Oct 2009 Location: Texas Posts: 581	How do I know if my ohm readings on fan and compressor mean good? That is a good meter. I used Fieldpiece for almost 20 years and I like them. I have one that looks like that. Do you have 240VAC at the breaker? If you have a SquareD breaker type disconnect out by the condenser, that's probably the problem. Check for 240vac to it and 240vac from it. Turn off the breaker and Ohm T1 and T2 to ground. If it shows to have a short, start isolating individual wires. I don't think it is the motor or compressor but it could still be the wires to them or your crankace heater.

11-21-2009, 11:39 AM	#5
webejamin_1982 Newbie Join Date: Nov 2009 Posts: 7	How do I know if my ohm readings on fan and compressor mean good? I will not be going out there till monday, but where I got the volts was from the saftey breker by condenser. So you say pull out fuse pin block and ohm each leg to ground. If good it should read a resistance and if bad it will be over load right? Also how would I check crankcase heater. Also like I said I have not checked the breaker pannel inside itself to see If I am having power problems there. I have flipped the on and off a few times but have not checked the internal structure or noticable flaws in the breaker switch itself. Thanks again.

How do I know if my ohm readings on fan and compressor mean good?