How to independently check the serviceability of the refrigerator electric motor: step-by-step guide

The electric motor (compressor) is the “heart” of the refrigerator, on which the cooling of the chambers and the safety of food depend. If the unit stops freezing, makes strange sounds or does not turn on at all, the first thought is that the motor is broken. But how can you be sure of this without calling a specialist? In 60% of cases, the malfunction can be diagnosed independently, having a minimum of tools at hand.

In this article we will analyze 7 working methods of checking from visual inspection to testing the windings with a multimeter. You will learn which symptoms accurately indicate problems with the engine, and when the thermostat or start relay is to blame. We will also provide a table of resistances for popular models Atlant, Indesit, Samsung i LGso that you can compare your measurements with the norm.

Important: diagnostics requires accuracy. Never check the compressor windings under voltage - this can lead to a short circuit or electric shock. Perform all manipulations on a de-energized device!

1. Signs of a faulty electric motor: when is it time to check

Before disassembling the refrigerator, make sure that the problem is really in the motor. Here 5 key symptomsthat should alert you:

• 🔊 Loud hum or knocking during operation - may indicate wear of the bearings or jamming of the piston.
• ❄️ No cold in the chambers when operating compressor - the motor hums, but does not pump freon.
• ⚡ The refrigerator does not turn on at all (no relay clicks, no lights are on).
• 🔥 Excessive heating of the case compressor (so hot that it is impossible touch).
• 🕒 Operation cycles that are too short or long (turns on for 5 seconds and turns off or works without stopping).

If at least one of these signs appears, it’s time to move on to diagnostics. But first rule out simple reasons:

• 🔌 Check is the refrigerator plugged in (sometimes the plug falls out unnoticed).
• 🌡️ Make sure that the thermostat is not turned off (turn knob for minimum cooling).
• 🚪 Inspect door seal - if it is damaged, warm air gets inside and the motor runs without stopping.

⚠️ Attention! If the refrigerator Indesit or Beko with the system No Frost stops freezing, first check evaporator fan. Its breakdown gives similar symptoms, but repairs are cheaper.

2. Visual inspection: what can be seen without tools

Start with an external inspection of the compressor. It is located at the bottom of the refrigerator (usually the back) and is a black or gray metal cylinder with pipes and a terminal box. Here's what to pay attention to:

• 🔧 Motor housing —there should be no cracks, traces of oil or rust. Oil on the floor under the refrigerator indicates a depressurization of the system.
• 🔌 Condition of the wires - melted insulation or burnt contacts indicate a short circuit.
• 🧲 Start relay (small box on the compressor) - if it is cracked or smells like burning, it needs to be replaced.
• 🌀 Condenser fan (if equipped) - it should rotate freely by hand, without jamming.

Pay special attention pipescoming from the compressor:

• 🟢 Thick tube (discharge) should be hot during operation.
• 🔵 Thin tube (suction) - cold or slightly warm.
• ❌ If both tubes room temperature, freon does not circulate (possible leakage or motor jamming).

Also check if it is overheating compressor Normally it should be warm, but not scalding. If the body is so hot that it is impossible to hold your hand, this is a sign of interturn short circuit or overload.

3. Checking with a multimeter: step-by-step instructions

A multimeter is the main tool for diagnosing electric motor windings. You will need a device with a resistance measurement mode (ohmmeter). Follow this algorithm:

1. De-energize the refrigerator (remove the plug from the socket).
2. Remove the start relay from the compressor (usually secured with latches or one bolt).
3. Find the compressor terminals —there are three of them:
   • C (Common)—common terminal;
   • S (Start)—starting winding;
   • R (Run)—working winding.

Measure the resistance between the terminals:

• C-S (starting winding);
• C-R (working winding);
• S-R (total resistance).

Normal resistance values for most household refrigerators:

Refrigerator brand	C-S (Ohm)	C-R (Ohm)	S-R (Ohm)
Atlant, Birusa	20–30	10–15	30–45
Indesit, Ariston	15–25	8–12	23–37
Samsung, LG	10–20	5–10	15–30
Beko, Vestfrost	25–35	12–18	37–53

If the readings:

• 🔴 Equal to 0 —short circuit in the winding.
• 🔴 Infinity (OL) —winding break.
• 🟢 Within normal limits —the compressor is working (the problem may be in the relay or thermostat).

De-energize the refrigerator|Remove the start relay|Clean the terminals from oxidation|Check the integrity of the wires|Compare the readings with the table-->

⚠️ Attention! If the resistance between compressor housing and any terminal is not equal to infinity - this is breakdown to the housing. Such a motor is dangerous to life and requires immediate replacement!

4. Checking the starting relay: why the compressor does not start

In 30% of cases, the “non-working compressor” is actually working - the starting relay is to blame. It is responsible for starting the motor and protecting against overloads. To check the relay:

1. Remove it from the compressor (usually secured with latches or one screw).
2. Shake the relay - if something rattles inside, this is a sign burnt contacts.
3. Look at contacts:
   • 🔥 Burnt or melted - the relay must be replaced.
   • 🟩 Clean and shiny - the relay is working properly.

Ring with a multimeter in resistance mode:

• Between terminals C and S there must be resistance (see table above).
• Between C and the body - infinity (OL).

If the relay is faulty, it can be replaced with a similar one (for example, for Atlant a relay of Indesit the same power is suitable). The main thing is a match by:

• 🔌 Mounting type (on latches or screws);
• 📏 Dimensions (must fit tightly on the compressor);
• ⚡ Rated current (indicated on the relay label).

How to temporarily start a compressor without a relay?

For diagnostics, you can apply voltage directly to the terminals C i S, but no longer than 1-2 seconds! Long-term operation without a relay will burn out the windings. This method is only suitable for checking whether the compressor starts at all.

5. Diagnostics by sound: what do knocks and hums mean

The sounds that the refrigerator makes will tell you a lot about the condition of the compressor. Turn on the unit and listen:

• 🔊 Smooth hum —normal operation.
• 💥 Loud knocking when starting—wear of the piston group or loose fastenings.
• 🌀 Whistling or hissing —freon leak or valve jamming.
• 🔄 Cyclic clicking (turns on and off)—start relay or temperature sensor is faulty.
• 🚨 Strong hum without starting —the compressor is “jammed” (the winding is burnt out or the piston is rusty).

If the motor hums, but does not start, try the following:

1. Turn off the refrigerator for 10–15 minutes (sometimes the compressor “sticks” due to overheating).
2. Slightly shake the compressor housing - if it is stuck, this may help temporarily.
3. Check the voltage in the socket (should be 220–230 V).

⚠️ Attention! If the compressor Samsung or LG with inverter control emits high-frequency squeak, this may be the norm - such models work quieter, but with different sound characteristics.

6. Checking heating and current consumption

Overheating of the compressor is a common cause of failures. To assess its condition:

1. Turn on the refrigerator and let it run for 30–60. minutes.
2. Touch the compressor housing:
   • 🟢 Warm (40–50°C) - normal.
   • 🟡 Hot (60–70°C) - check ventilation and cleanliness of the capacitor.
   • 🔴 Scalding (>80°C) - interturn short circuit or overload.

Measure current consumption (current clamp is needed):

• The norm for most models is 0.8–1.5 A.
• If the current >2 A - the compressor is overloaded.

Causes of overheating:

• 🧹 Dirty capacitor (dust on the grill at the back of the refrigerator).
• 🔥 High voltage in the network (>240 V).
• 🌀 Fan malfunction (for models with forced cooling).
• 🛠️ Compressor wear (natural after 10-15 years of operation).

7 When self-checking does not help: signs of serious breakdowns

Not all faults can be diagnosed at home. Contact a specialist if:

• 🔧 Compressor jammed (the shaft does not rotate even when voltage is applied directly).
• ❄️ In the system no freon (tubes are at room temperature, the motor is running but not cooling).
• ⚡ Yes breakdown on the casing (the multimeter shows the resistance between the terminals and the metal casing).
• 💥 Burnt out winding (blackened wires, burning smell).
• 🔄 Refrigerator turns on for 1-2 seconds and turns off (leakage or system blockage is possible).

In these cases you will need:

• 🔧 Replacement of the compressor (cost - from 5,000 to 15,000 rubles, depending depending on the model).
• ❄️ Refilling with freon (2 000–4 000 ₽).
• 🔌 Repair or replacement of the control board (relevant for modern electronically controlled refrigerators).

⚠️ Attention! In refrigerators No Frost with an inverter compressor (for example, Samsung RB30J3000WW), diagnostics are more complicated - such motors are controlled by an electronic board, and a special tester is needed to check.

FAQ: Frequently asked questions about checking the electric motor of a refrigerator

Is it possible to check the compressor without removing it from the refrigerator?

Yes, most checks (visual inspection, measuring resistance, checking relays) can be performed without dismantling. However, to accurately diagnose an interturn short circuit or breakdown on the housing, sometimes it is necessary to remove the compressor and test it separately from the refrigerator.

What is the resistance. should be between the compressor terminals?

For most domestic refrigerators:

• C-S: 15–35 Ohm (start winding);
• C-R: 8–20 Ohm (running winding);
• S-R: the sum of the two previous values (23–55 Ohm).

See the exact data in the table above or on the compressor nameplate.

What to do if the compressor hums but does not start?

Possible causes and solutions:

1. The starting relay is faulty —replace (cost 500–1,500 ₽).
2. The compressor is jammed —try to wedge it (with light blows to the body) or replace it.
3. Low voltage in the network —check the socket, use stabilizer.
4. Winding break - the compressor needs to be replaced.

How to distinguish a compressor malfunction from a freon leak?

Signs of a leak freon:

• The compressor works without stopping, but does not cool.
• The suction tube (thin) is not cold, but at room temperature.
• Oil stains are visible at the place where the tubes are soldered (freon leaves along with the oil).

When If the compressor malfunctions, it either does not start, or it heats up and turns off due to protection.

How much does it cost to replace a compressor in a refrigerator?

The cost depends on the model and region:

• Budget refrigerators (Atlant, Birusa) — 5 000–8 000 ₽.
• Average class (Indesit, Beko) — 8 000–12 000 ₽.
• Premium models (Samsung, LG with inverter) - 12,000–20,000 ₽.

The price includes the work of a master + a new compressor. Sometimes it is cheaper to buy a used refrigerator.