About 2 stage coil

[cstyx]

Hi,
Would like to know 2 stage compressor coil which mark 1,2,3 and 7,8,9, is there any difference if i connect it 789 as first step in and 123 as second step in.

Last week one of my customer 30hp 2 stage compressor burn down, i removed the coil which mark 123 as R,Y,B line (first step contactor) and 7,8,9 as RYB line (second step). Then, they passed me a secondhand 30hp coil without numbers but with 3 phase colour for both step.

I checked both coil with same ohm, check contactor contact point and changed all the necessary things like oil, filter and etc.then fixed it back. When start both part running at 16-18amp, when it getting colder dropped to 14amp, next day i changed another filter everything running smoothly, but till evening the coil burn down again (first step coil).

So would like to know 2 stage compressor coil which mark 1,2,3 and 7,8,9, is there any difference if i connect it 789 as first step in and 123 as second step in . ? I installed this system coming 4 years and this is the first time it burn down.

[GHAZ]

hello mate if its standard 50/50 part wind it doesnt matter but if you have for example copeland awm=66/33 or Bwm=60/40, then you have to wire in the first contactor to the biggest half of winding ,otherwise it will burn out under load because it wont be able to get away. But also check if the second contactor is comming in after about a second,to make easy to check what windinds you have is ,50/50=same ohms reading across both sets of pins,and if you got the newer types of part winds the three pins with lowest ohms readings are the biggest halfs,they must be first step in

[cstyx]

Hi GHAZ,
Same ohms, carrier compressor. They bring me to have a look at the compressor where they get the coil, it's a 30hp carrier compressor but not 2 stage type. I don't see any amps difference when starting and running betw the 2 coil. So can you figure out what's the problem here?

One more question, how to specify carrier compressor HP other than looking at the coil label?

[GHAZ]

Hello mate if you give the correct model number of compound compressor and the one you took the coil out of and the stator core length of both,and i can then tell you the horsepower