Restoring the functionality of a refrigeration unit often comes down to a malfunction of the starting device, and knowing how to correctly assemble a refrigerator relay becomes a critical skill for a home craftsman.
Incorrect assembly of this unit can lead not only to repeated failure, but also to burnout of the electric motor windings, so each stage of installation requires extreme care and compliance with technological standards.
In this material we will analyze in detail the process of assembling various types of starting devices, paying special attention to the nuances of fixing the contacts and the correct positioning of the moving elements of the mechanism.
Diagnostics and preparation for assembly work
Before starting assembly, you must make sure that all internal components of the relay are in good condition, since the installation of defective parts does not make any sense.
Carefully inspect contact group for the formation of soot or melting, since even microscopic Irregularities on the metal surface can cause sparking and sticking of contacts during operation.
Check the integrity of the nichrome spiral or the condition of the bimetallic plate depending on the type of your device, because these elements are responsible for timely opening of the circuit.
⚠️ Attention: If marks are visible on the relay body thermal destruction of plastic or a burning smell, it is absolutely impossible to assemble such an assembly - a complete replacement of the component with a new one is required.
Make sure that the movable core moves freely inside the coil and does not get stuck due to oxides or mechanical damage, which often happens during long-term operation.
Carefully clean all parts from dust and oxides using fine sandpaper or a special contact spray to ensure ideal conductivity of electrical current.
Assembling an induction starting relay
Induction models, often called relays with a coil, require precise orientation during installation, since their work is tied to the gravitational effect on the movable core.
Install electromagnetic coil strictly vertically in the housing seat, making sure that its leads fit tightly to the contact pads without distortions.
Carefully place the movable core inside the coil, making sure that it does not touch the walls and can move freely up and down under the influence of the magnetic field.
- 🔧 Make sure that contact bridge is installed on the correct side to ensure that the circuit is closed when the core is lifted.
- 🔧 Check the tension of the return spring, which should return the core to the lower position after starting the motor.
- 🔧 Fix the top cover of the housing, ensuring the alignment of the guide grooves to prevent distortion of the mechanism.
When During assembly, it is important not to overtighten the cover fastening screws, so as not to deform the plastic case and not disrupt the geometry of movement of the internal parts.
The final stage will be to check the ease of movement of the entire assembled mechanism by gently rocking the device.
Nuances of installing a thermal protective relay
Thermal relays work on the principle of expansion of a bimetallic plate when heated, so the tightness of the heating element to the plate plays a decisive role.
During assembly, it is necessary to ensure maximum contact between heating coil and bimetal, since the speed of the protection reaction to overcurrent depends on this.
Install the moving contact on the bimetallic plate, fixing it in special grooves so that when the plate is bent, the circuit is guaranteed to open.
| Relay element | Function during assembly | Critical parameter |
|---|---|---|
| Bimetallic plate | Opening the circuit when overheated | Point bending |
| Heating coil | Heat transfer to the plate | Contact density |
| Moving contact | Power circuit switching | Force pressing |
| Housing | Fixation of all elements | Tightness |
Assemble the housing, making sure that all current-carrying parts are securely isolated from the outer walls and have no play.
Check whether the wires are pinched inside the case, as this may lead to a short circuit or disruption of the heat dissipation.
Why does the thermal relay get hot?
If after assembly the relay gets hotter than usual, you may have installed the heating coil incorrectly, and it does not transfer heat to the plate, but heats the case. Or a relay has been selected with a lower rated current than the compressor requires.
Assembling a posistor starting device
Posistor relays are considered the easiest to assemble, since they do not contain moving mechanical parts, but work by changing the resistance of the crystal.
The main task during installation - ensure reliable electrical contact between the terminals posistor and terminals for connecting the compressor windings.
Insert the ceramic element into the housing so that it sits tightly in the socket and does not loosen, which can lead to mechanical destruction of the fragile crystal during vibration.
- 🔌 Connect the wires to the appropriate terminals, observing the marking S (Start) and R (Run) for correct phasing.
- 🔌 Make sure that the spring contacts tightly press the posistor terminals to minimize transition resistance.
- 🔌 Close the case, securing it with latches or screws to prevent moisture from getting inside.
Despite the absence of mechanics, it is important to check the integrity of the wires going to the posistor, as they often overheat and lose elasticity.
After assembly, it is recommended to ring the device with a multimeter to make sure there are no short circuit between the contacts.
⚠️ Attention: The posistor remains hot after operation; carry out assembly and testing only after the element has completely cooled down to avoid burns.
Connecting the assembled unit to the compressor
After successful assembly of the relay, it is necessary to correctly install it on the compressor, which is one of the most critical moments of the entire repair process.
Place the assembled device onto the three pins of the compressor, observing the orientation indicated by the arrow UP or the inscription TOP on the relay body.
Do not apply excessive force when putting on, so as not to break the ceramic insulators or bend the contacts inside device.
Connect the power wire to the appropriate terminal using reliable crimping or soldering, as poor contact will lead to heating and repeated failure.
Fix the relay with a metal bracket or plastic holder if the design of your refrigerator provides for additional fasteners.
☑️ Check before switching on
Testing and initial launch of the system
The final stage is a test run of the refrigerator, which will allow you to evaluate the quality of the assembly and the correct selection of components.
Plug in the unit and listen carefully to the sound startup: the compressor should start with a characteristic hum, and after 2-5 seconds the starting relay should click, turning off the starting winding.
If you hear a crackling or buzzing sound without starting the motor, immediately turn off the power, as this indicates a malfunction in the assembled unit or problems with the compressor.
Check the heating of the relay housing after 10-15 minutes of operation: it should not be excessive, only light heat is allowed.
Make sure that the refrigerator begins to gain temperature and cold appears in the chambers, which confirms the full functionality of the repaired system.
Is it possible to assemble a relay if the coil is burned out?
No, if the winding of the inductive relay coil has burned out or the posistor has burned out, assembling the old case will not help - you need to replace the internal element or the entire device, since it is impossible to restore the burnt out winding at home.
Why does the relay fall out of the case during assembly?
This happens if you align the guides incorrectly grooves or forgot to install the retaining spring; The reason may also be broken plastic case latches, which will have to be restored using heat-resistant glue.
Do relay contacts need to be lubricated during assembly?
Ordinary contacts do not need to be lubricated, but the movable core of the induction relay can be lightly lubricated with heat-resistant silicone grease to prevent sticking, but it is important do not overdo it so that the lubricant does not get on the electrical contacts.
How to understand that the relay is assembled incorrectly?
The main signs of erroneous assembly are the absence of a click to disconnect the starting winding, a constant crackling sound, sparking inside the housing or the failure of the compressor to start when there is voltage at the input.