wiring up a compressor.

[ceilingwall]

Hi, Have I got one for you, this is a long standing problem, I have a workshop with 3 phase supply, the compressor is 3 phase, now this is the problem and I have had two sparks in to get it to work on the pressure switch, the main problem is no one seems to know where the two black wires that come from the pressure switch go to in the star-delter switch, the three main live feeds go to the right side and the feed to the compressor on the left, it works fine if you press the start button and it runs to the set pressure on the pressure switch and you see and here it click as if it was trying to turn off, but with the two wires from it going nowhere then it will not, if anybody knows please let me know, as I have someone watching the pressure and turning it off when it get close to the required pressure, thanking you before hand. Cheers Ernie.

 

[Spark123]

I think you'll find you need to bypass the start push button with the N/C contact of the pressure switch and remove the retaining contact on the control contactor. When doing this you also need to consider alternative means for emergency stopping as the original stop button on the star delta starter will no longer be appropriate as upon releasing the stop button the machine will auto start. Installing a DOL wired starter prior to the star delta starter for this purpose will achieve this.

 

[Belle427]

would also benefit you to have a suitable isolator in the circuit wired into the control if it doesnt have one for maintenance purposes

 

[Maxxy]

I'd also recommend fitting a pressure relief valve into the compressor, or into the receiver it feeds.

Your best bet is probably to get in touch with the manufacturer, and get a new installation manual sent through if you dont have the old one for reference. Compressors often have a stand by mode, where by they keep spinning, but go into an energy saving mode. Cutting the power to these wrongly will bugger it up over time, and will cause even more problems

All depends on the make and size though

 

[ceilingwall]

Hi, Lads thanks for your replys I will give spark123 suggestion a try and see if this works, regarding ch427 it as a inline isolator as required by law, plus maxxy it already as a pressure relief valve on the tank, but thanks for your replys again, if you need to know anything about woodwork or building I will try to held. Cheers. Ernie