The difference between aluminum shell resistors and wire wound resistors

Customers often ask how to choose between aluminum shell resistors and wire wound resistors. Here I analyze the characteristics of these two resistors as follows, hoping to help you choose.

Overview of aluminum shell resistors

Aluminum shell resistors, the shell is made of aluminum alloy (gold aluminum shell), with heat dissipation grooves on the surface, small size and high power, high temperature resistance, strong overload capacity, weather resistance, high precision, standard low induction resistance, high stability, strong architecture, good flexibility, multiple combination options, conducive to mechanical protection, convenient installation and use.

The role of the aluminum shell in the aluminum shell resistor is cooling. The thermal conductivity of metal aluminum is very good. It can quickly transfer the heat generated by the resistor when it conducts electricity to the surface of the resistor body and continuously dissipate heat through the air. The surface of the aluminum shell is designed with more heat dissipation grooves, which increases the heat dissipation surface area and increases the heat dissipation capacity.
The good plasticity of aluminum metal also allows aluminum shell resistors to adapt to better size changes when adapting to the installation space.
The filler of the aluminum shell resistor is insulating silicide, which can absorb a certain amount of heat in an instant. Reach several times the power of the resistor in an instant.

Overview of Wirewound Resistors

Wirewound resistors use ceramic tubes as skeletons, and alloy resistance wires are evenly wound on the skeletons. The surface has high-temperature resistant insulating paint, which is easy to install.

The low resistance of the wirewound resistor is 20 ohms-50 ohms. The resistance wire can be pressed into a corrugated shape and stand on the ceramic substrate, thereby increasing the available area of ​​the winding and having better heat dissipation performance.

The difference between the performance of aluminum shell resistors and corrugated resistors

Comparison of heat dissipation capacity when powered on instantly

Aluminum shell resistors have fillers that can absorb heat. After powering on for 1s, the surface temperature of aluminum shell resistors will be lower than that of wirewound resistors with the same power.

Comparison of heat dissipation capacity when powered on for a long time

In the case of long-term power-on, the advantages of wirewound resistors are very clear. Since the resistance wire of the wirewound resistor can be almost directly in contact with the air (the spacer is only insulating paint), the heat dissipation capacity of long-term power-on will be clearly better than that of aluminum shell resistors.

Comparison of insulation performance
In the structure of aluminum shell resistors, there is an insulation layer between the resistance wire and the aluminum shell. The insulation performance can reach a leakage current of less than 2mA between 1500V-4000V according to different requirements, and the insulation performance is very good.
The structure of the wire-wound resistor is that there is a layer of insulating paint on the resistance wire. The insulation performance is below 500V, and the insulation performance is unreliable, and it is not suitable for exposure to touchable positions.

Structural comparison
The structure of the aluminum shell resistor is stronger than that of the wire-wound resistor, and the vibration resistance is better.

Comparison of installation convenience
The aluminum shell resistor is smaller in size than the wire-wound resistor, has good insulation performance, and a stronger structure, which can be suitable for working in more complex environments.

Comparison of costs
The cost of the wire-wound resistor with the same power is lower than that of the aluminum shell resistor.

Comprehensive comparison
The aluminum shell resistor has more advantages in instantaneous power-on, insulation performance, structural stability and installation convenience
The wire-wound resistor has obvious advantages in long-term power-on performance.

When choosing, we can make the following suggestions based on different workstations:
It is recommended to use aluminum shell resistors for motor braking in complex sites.
Use aluminum shell resistors when the installation space is limited.
Use aluminum shell resistors when earthquake resistance is required.
Use aluminum shell resistors when power is turned on instantly and there is a surge.
Use wire winding resistors for long-term loads.
Use wire winding resistors when costs are limited and safety protection is required.