2024 Author: Howard Calhoun | [email protected]. Last modified: 2023-12-17 10:16
A differential machine serves as a powerful protective force against the damaging effect of electric current on the human body. It combines the functions of an automatic breaker and a residual current device (RCD). The action of this machine is aimed at protecting the wiring from overload, short circuits, as well as protecting a person from electricity when he enters a high voltage area and touches current-carrying equipment elements.
How to choose the right differential machine
Currently, these devices are preferred with high breaking capacity (3000 A for specified termination devices, 6000 A for group devices) and protection against neutral conductor damage. If there are several lines of electricity consumption in the room, then it is better toeach of them separately to connect the differential machine. You should first find out the internal voltage of the network, calculate the total power of household and lighting devices that will be connected to this line, and then buy the specified device.
The main points of choosing a machine
- The base (nominal) voltage of the device must correspond to the indicator for which this network is designed. This is an important condition. For a single-phase network, this is at least 230 V, and in the case of a three-phase network, it is within 400 V.
- The indicator of the maximum allowable (rated) current of the differential machine should not be greater than that of the corresponding electrical circuit. This will avoid network overload, overheating of conductive and insulating parts.
Procedure for self-disabling of the specified device
- Inspect the machine and determine the cause of the shutdown (mains overload, short circuit, current leakage).
- Push the reset button into the case after the cause of the safety shutdown has been eliminated.
The principle of operation of the device
Let's take a closer look at how the differential machine works, the connection diagram of which is the same as in the RCD. The principle of operation of the device is to compare the electric currents passing through the phases "L" and "N" (zero).
This is an important factor in this case. If the system is working properly, that is, electrical appliances and wiring are not broken, then the indicators will be identical. If there are problems with the current output, these values will differ significantly from each other. The differential automatic device will independently determine the discrepancy that has arisen and, if the nominal leakage rate is exceeded, the power supply will turn off automatically. This is an important feature of this device. If a safety shutdown occurs, you should deal with the cause, and then turn on the device.
Tip
The differential machine must have a solid body (without dents, cracks and other defects), mandatory marking on it corresponding to the required parameters, and the mechanism responsible for turning the device on and off must be in working order.
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