Wire wound resistors are a type of fixed resistors. Wire-wound resistors are constructed by winding resistance wires on an insulating frame. The resistance wire is generally made of nickel-chromium, manganese-copper alloys with a certain resistivity. The insulating frame is made of ceramic, plastic, metal coated with insulating layer and other materials into various shapes such as tube shape and flat shape. The resistance wire can be wound on the skeleton in one layer or multiple layers as needed, or the non-inductive winding method can be used. Wire-wound resistors are mainly used for voltage division, voltage reduction, shunting and load resistance in AC and DC circuits such as precision instruments, telecommunications instruments, and electronic equipment.

structure

Wire wound resistors are a type of fixed resistors. Its circuit symbol is the same as ordinary resistance. Its innermost layer is a glass fiber core column with a resistance wire wound on the core column. The two end wires of the resistor are crimped together with the soldering foot leads inside, and the outer layer is sealed with an insulating packaging filler.

Features

(1) The resistance wire is made of constantan, manganin, nickel-chromium and other alloy materials, which has good stability and overload capacity.

(2) A crimping method is used between the resistance wire and the welding foot lead. If the load is short-circuited during application, it can quickly fuse at the crimping point to protect the circuit.

(3) Due to the use of industrial high-frequency electronic ceramic shell and mineral material encapsulation, it has excellent insulation performance, the resistance can reach more than 100MΩ, and the heat dissipation is good, and the power is large.

(4) The resistance wire is tightly encapsulated inside the ceramic resistor body, which has excellent flame-retardant and explosion-proof characteristics.

Detection method and substitution of wire wound resistor

The method and precautions for detecting wire wound resistors are exactly the same as those for detecting ordinary fixed resistors. Wirewound resistors generally work under high current conditions, so the damage rate is relatively high. When it is blown out and damaged, if there is no original matching type resistance replacement, the following methods can be used for emergency replacement according to the circuit requirements:

(1) For the high-power and low-resistance wire wound resistors that have been disconnected, the surface insulation layer can be scraped off to expose the resistance wire and find the break point. Retreat the resistance wire at the break point by one turn and twist it tightly.

(2) Emergency replacement with resistance wire. The resistance wire surface can be removed from the old wirewound potentiometer or wirewound resistor. Use a multimeter to measure a piece of resistance wire with the same resistance value as the original resistor, and wind it on the original resistor. After the two ends of the resistance wire are respectively welded to the two ends of the original resistor, install it into the circuit.

(3) When the resistance of the damaged wire wound resistor is large, an internally heated electric soldering iron core can be used instead. If the resistance does not meet the circuit requirements, the electric soldering iron cores can be connected in series and parallel to solve the problem. As long as the resistance is similar, it will not affect the normal operation of the circuit.