Single Phase Puzzle to challenge you

[Sprintst3000]

Hi
I have inherited a compressor with a single phase motor but its been stripped and I need to fathom out what's what.. I don't know if it even works as why did they take it apart and if its broken what's wrong!

I have a start and a running capacitor



A reset switch

Simple push button

Two cables with 2 and 3 wires respectively



So can anyone give me guidance on testing then rewiring this puzzel please!

 

[MDJ]

first question to you, have you got any test equipment and if so do you know how to use it?

 

[Sprintst3000]

first question to you, have you got any test equipment and if so do you know how to use it?

Yes I have a multimeter and I have reasonable but maybe dangerous ability. ... I have measure the resistance between some points and I have O/C between the brown, 5.6ohms between brown and black (Both browns) 4.4ohms between the yellow and browns, 2ohms between black and yellow and finally 1.3ohms between black and blue

 

[MDJ]

Yes I have a multimeter and I have reasonable but maybe dangerous ability. ... I have measure the resistance between some points and I have O/C between the brown, 5.6ohms between brown and black (Both browns) 4.4ohms between the yellow and browns, 2ohms between black and yellow and finally 1.3ohms between black and blue

a multi meter is of no use, you need to whack 500 volts between the windings and earth just to start with, then between windings and if good then start looking at other things, could be many reasons why it is not working, we cannot advise you what is wrong on here without seeing and testing it, we can suggest things all night but a multi meter reading whatever it says IME is pointless regarding testing a motor for faults

 

[Sprintst3000]

a multi meter is of no use, you need to whack 500 volts between the windings and earth just to start with, then between windings and if good then start looking at other things, could be many reasons why it is not working, we cannot advise you what is wrong on here without seeing and testing it, we can suggest things all night but a multi meter reading whatever it says IME is pointless regarding testing a motor for faults

Well assuming the coils haven broken down to earth could we at least sort out the wiring! I was expecting to see two coil resistance values.

 

[MDJ]

Yes I have a multimeter and I have reasonable but maybe dangerous ability. ... I have measure the resistance between some points and I have O/C between the brown, 5.6ohms between brown and black (Both browns) 4.4ohms between the yellow and browns, 2ohms between black and yellow and finally 1.3ohms between black and blue

also there are several items which could be a problem, bearings, brushes, armature, shaft, windings shorting to earth, a multi meter not sufficient to check this bit of kit out

 

[brianmoooore]

Also, your results don't make sense. If you have 5.6 ohms between black and each brown, then the maximum you are going to see between the two browns is 2 x 5.6 ohms =11.2 ohms, not O/C.

 

[Sprintst3000]

also there are several items which could be a problem, bearings, brushes, armature, shaft, windings shorting to earth, a multi meter not sufficient to check this bit of kit out

Bearings = Good
Brushes = Good
Armature = not sure
Shaft = Good
Windings = Not sure
Motor age = 2021
Usage = light
Mechanically excellent
Clean
Wiring - not wired at all

 

[Sprintst3000]

Also, your results don't make sense. If you have 5.6 ohms between black and each brown, then the maximum you are going to see between the two browns is 2 x 5.6 ohms =11.2 ohms, not O/C.

I did fear that there is a break but I don't have the confidence in my wiring/fault finding ability without a circuit diagram .. I might take it apart and check for the obvious

 

[westward10]

It has brushes?!

 

[nicebutdim]

It has brushes?!

OP did state this was a puzzle.

 

[brianmoooore]

I've been asked to 'look at' a few of these DIY type compressors over the years, and the usual scenario is that one of the capacitors has failed. Replace it, and it'll run for a week, until the replacement capacitor fails as well, which is probably because the winding has developed a few shorted turns.
These tend to be cheap and nasty single phase motors, which aren't really single phase at all. They are modified three phase motors, using the run capacitor produce a phase change and simulate a poor three phase supply.

 

[DefyG]

Photo of the name plate might help

 

[Marvo]

Have you got the lid of the connection box on the motor? Often there's a wiring diagram inside the lid.

What is the make and model number of the motor? Somewhere on the motor there should be an information plate, can you post a pic of it please?