The resistance box is a resistance measurement instrument with a variable resistance value, and its resistance value can be changed by a certain step within a known range. The resistance element of the switch type DC resistance box is connected between each contact and is fixed on each rotating contact, and the brush moves on the contact.
The resistance used in such a resistance box is the resistance between the initial contact and the contact that the brush touches during use.
Resistor box support has a potential lead-out that can be verified by the component. The contact ring, the contact piece and the brush in the switch are all pressed with a micro-spring. Therefore, after long-term use, the contact resistance will be less deteriorated. The support is made of high-insulation polysulfone, the insulation performance is good, and the reading on the panel shows Arranged in two straight lines and a simple readout value, the zero resistance is 0.01 ohms when all the transfer switches of the resistor box are in zero position. Therefore, the minimum step switch has no zero, starting from 1 and the zero resistance must not be deducted from the measurement result during use. The resistance element is made of high-stability manganese-copper alloy wire wound on a ceramic tube. After strict processing, it has high stability. Shengxu DC resistance box is widely used in schools, industrial and mining enterprises and research institutes for measurement and other experiments. use.
DC resistance box operation procedure
1. Before using the resistor, turn each group of knobs several times so that the switch contacts are in good contact.
2. The resistor is led by two terminals. Each terminal has two knobs. When the resistance is high, the two-wire system can be used. When the resistance is low, the four-wire system must be used to ensure the accuracy of the resistor.
3, resistors in use, can not exceed the nominal power, and can only be connected in the DC circuit.
4. The resistor should be stored in an environment with an ambient temperature of 10~30Â°C and a relative humidity of less than 75%. Indoor air should not contain gases and harmful impurities that can corrode the instrument, and the instrument should not be exposed to direct sunlight.
5, resistance box in the use of the process should be regularly used cotton with a small amount of oil applied to the switch contacts and brushes, but not too much.
6, when the resistance box is used, pay attention to the knob adjustment order, do not over-regulate
7, the use of environmental conditions:
Reference conditions: temperature 20Â±0.5Â°C, relative humidity 40%~75%
Nominal condition: temperature 20Â±10Â°C relative humidity 25%~80%