A contactor is defined as an electrical relay used to manage the circulation of power in a circuit. Lots of people likewise refer to them as a relay. A relay is actually defined as a tool that replies to a little existing or voltage change by turning on switches or various other devices in an electric circuit.
In the real world of home heating and cooling, what this implies is a contactor is capable of dealing with a higher existence than a relay. Relays are normally scheduled for small pilot duty applications. Many home heating and air conditioning service technicians will certainly not call a contractor a relay.
We will be going over a typical solitary post or double post contactor as would be discovered in a modern-day residence utilizing a split system gas heater with a/c or a heat pump. Single posts have only one set of contacts while dual posts have two. Single posts are used by many makers of devices. Solitary posts just damage half the power to the fan electric motor and also compressor while dual posts break all of it. We feel most home heating as well as air conditioning service technicians probably like breaking both sides, a minimum of what we do.
Contactors actually contend the very least two different circuits in them. (Some business contractors have many circuits). One circuit is the low voltage coil circuit and the various other is the tons circuit.
The coil circuit in the majority of home a/c or heat pump systems utilizes a 24-volt coil, nevertheless, there are some systems that utilize a 230-volt coil in conjunction with a little relay that switches over the contactor on and off. These 230-volt coil systems are primarily on older systems or commercial units nowadays. Before transforming any contactor make sure the proper coil voltage is used or a charred coil might result. The coil voltage will be noted on a small tag on the side of the contactor.
The line/load circuit in the residence contactor is made used to supply 230 volts to the load side of the devices from the line side. Simply put, the main 230-volt power originating from the power source of the home moves throughout the calls in the contactor to the line side (compressor, follower motor, and any other element) when the coil is stimulated by a telephone call from the residence thermostat for cooling or in a heat pump for air conditioning or home heating.
When the thermostat isn’t asking for the unit to be running, the coil launches, as well as the contacts, open triggering the compressor as well as the fan electric motor to quit.
Countless on and off cycles nevertheless, trigger a couple of problems. The most evident issue is that the get-in touches with themselves obtain melted from frequently arching as they open and shut the 230-volt connection. Getting in touch with them can really bond themselves shut after an amount of time. These hundreds of cycles additionally trigger the plastic moving device to wear. If you’d like more information, check out berkeys.com/perot-museum-of-nature-and-science-dallas/
This wear often creates the contactor calls to stick closed although the thermostat has actually quit sending out an electric signal to the coil. When this happens it usually goes undetected by the house owner as well as can rapidly cause a frozen evaporator coil and or compressor. When a frozen problem exists the oil in the compressor is additionally frozen and can not oil the inner components inside the compressor.
This condition amounts to the very same thing as running your automobile without oil! The various other issues with charred contacts are that there may be a voltage drop and also included warm sent to the compressor and also fan electric motor since the calls are scorched.