Refrigerator electrical equipment and service
Refrigerator Repair – Electrical test procedures
Supply and control switch
1. Check the electrical supply at the power point, the fuse and the fuse rating.
2. Ensure that the control switch is set to the on position, and check the
electrical supply to the control. If there is supply to the input side of the control, bridge out the control contacts with a jumper [...]
Refrigerator Repair – Motor protection
The most common cause of motor failure is overheating. This condition is created when a motor exceeds its normal operating current flow. The result can be either a breakdown of the motor winding insulation and a short circuit, or a winding burn-out. For this reason, overload protection is provided in the form of a current [...]
11Nov2009 | admin | 0 comments | ContinuedRefrigerator Repair – Centrifugal switch (open-type motors)
This form of starting device is used on open drive motors. It comprises three major components: the switch contacts, the moving contact arm and the governor assembly (see Figure 41).
The switch contacts are wired in series with the supply and the start winding.
The governor assembly is mounted on the motor shaft. It consists of a [...]
Refrigerator Repair – Capacitors
Those normally used on smaller units are of the electrolytic type. They can be considered as being an electrochemical component employed to improve the phase angle relationship between the motor windings when the motor starts and runs.
They may be installed in a series or parallel with the motor windings. If a specific capacitance is not [...]
Refrigerator Repair – IC-22 relay
This is another form of solid state relay for non-capacitor and capacitor start motors. It can be used as a replacement for the conventional types.
The normal operating temperature of the semiconductor is approximately 76o C or 170o F Therefore care must be taken when handling if the compressor is running.
Installation for non-capacitor start motors [...]
Refrigerator Repair – Positive temperature coefficient (PTC) device
Many commercial motor compressors have this type of starting device. In most cases the motor is designed with an internal overload protector; this gives better protection against overload conditions since it is more sensitive to the temperature of the motor windings. It is less current sensitive than the external overload protector.
When the compressor starts, resistance [...]
Refrigerator Repair – Potential (voltage) relay
This type of relay is used with high starting torque motors. It operates in a similar manner to the current relay except that the switch contacts are normally closed. The solenoid coil, once energized, maintains a magnetic force strong enough to open the switch contacts and keep them open whilst the compressor is running.
The relay [...]
Refrigerator Repair – Current relay
This can best be described as a magnetic switch. It comprises a small solenoid coil around a sleeve and an iron core. Inside the sleeve is a plunger to which the switch contact bridge is attached; the contacts are normally open.
When the coil is energized, a strong magnetic field of force is created because the [...]