Auxillary Contactor

[kevinfitz06]

Im just getting into the refrigeration field, I am getting exposed to supermarket refrigeration mainly. So that means I will be working on rack systems. I got a chance to look at a control panel and was simply amazed. One question that has been bugging me is what the function of an auxillary contactor is? Basically there were three breakers for each of the compressors, but there were four contactors, and i was told thats an auxillary contactor... I didnt get a chance to ask why it is used. All what was told to me dont have both of them engerized. Can anybody help me out?

[Magoo]

Try a career change to something that you understand and are comfortable with.

[Brian_UK]

Perhaps it is relating to the motor starter.

Depending on size the start method changes, try looking at start/delta or part wind starting systems.

[vadivelan]

Hi Kevin welcome to the site. The term auxillary contactor normally used when the cotactor is used in the control circuit for performing a logical operation rather than used as normal power contactor.

[Peter_1]

Try a career change to something that you understand and are comfortable with.

Magoo, this is what this forum was made for, asking questions. easy and difficult ones, clever and stupids, long and short questions. But every question is a hunger to information and help.

[monkey spanners]

Im just getting into the refrigeration field, I am getting exposed to supermarket refrigeration mainly. So that means I will be working on rack systems. I got a chance to look at a control panel and was simply amazed. One question that has been bugging me is what the function of an auxillary contactor is? Basically there were three breakers for each of the compressors, but there were four contactors, and i was told thats an auxillary contactor... I didnt get a chance to ask why it is used. All what was told to me dont have both of them engerized. Can anybody help me out?

Just a thought that i'm wondering, you say the comps have three breakers, so i assume they are three phase comps, then you say they have four contactors, this could be for star delta starting as this needs three contactors and a timer and as said the fourth one would be for some other function, such as a head cooling fan or something,

or, and this is what i was wondering,

If you mean contacts and not contactors, that is to say a four pole contactor where three are used for the three phase power to the comp and the fourth contact could be for many other things, it could be a normally closed contact so it is on when the comp is off, this would be for the crank case heater, or maybe its could be a normally open contact that opens the oil return solenoid when the comp is running.

There are many possibilities.

[Magoo]

Magoo, this is what this forum was made for, asking questions. easy and difficult ones, clever and stupids, long and short questions. But every question is a hunger to information and help.

Hi Peter.
My post was based around the fact that in the feild self training is not the place to learn control systems and functions of components. With all the health and safety requirements, personal risk and public risk, the reality is do not do anything that you do not understand or are qualified to undertake technically. Simple instruction with an electrical drawing is far safer for everyone. Supervised instruction.

[sachin230]

what the function of an auxillary contactor is?

A contactor is an electrically controlled switch used for switching a power or control circuit.

An additional motor starter contact used to provide memory to control circuits. When energized, the motor starter closes the auxiliary contact, maintaining a closed/open circuit depending upon normaly open & Normaly closed contact.

Try to understand the panel electrical ckt diagram.