Electric circuits for switching lamps
Let's look at simple circuits for controlling electric lamps. Two or more lamps can be connected to the network with one single-pole switch (Fig. 1, a). The control of five lamps using two single-pole switches located nearby (Fig. 1, b) is carried out as follows. Turning on the first switch turns on two lamps, and flipping the second switch turns on the other three. Such a lamp switching scheme is used in large rooms with an operating mode that requires different degrees of illumination.
If it is necessary to sequentially change the number of included lamps, they are connected to the network using a brightness switch (Fig. 2). With the first turn of such a switch, one of the three lamps is turned on, with the second, the remaining two, but the first lamp is turned off, with the third, all lamps are turned on, and with the fourth, all lamps on the chandelier are turned off.
Rice. 1. Electrical and electrical schemes for connecting electric lamps to the network: a — one switch; b — two switches
Rice. 2.Electrical and wiring diagrams for connecting electric lamps to the network with one shine
If independent control of one or more lamps from two locations is required, use a circuit with two switches connected by two jumpers and a wire (Fig. 3).
Rice. 3. Electrical and circuit diagram for connecting lamps to the network with two switches
Lamps of lighting electrical installations powered by a three-wire three-phase current system are connected between two phases of the network, and installations powered by a four-wire network - between the phase and neutral wire (Fig. 4).
In lighting electrical installations of industrial enterprises, remote and automatic control is used if necessary for the working conditions or to ensure the safety of people. An approximate scheme of remote control of the working lighting network and automatic switching on of the emergency lighting network of the electrical installation is shown in fig. 5.
In the diagram, the working and emergency lighting networks have separate power from different power sources.
There are 2 remote control devices in the working lighting network that allow you to turn the power on and off from the central control panel. Devices 4 installed in the emergency lighting network are connected to the working lighting devices so that they automatically turn on the emergency lighting when the voltage in the working lighting network disappears.
Rice. 4. Schemes for connecting electric lamps to a network with linear (a) and phase (b) voltage
Rice. 5.Scheme of connection to the network of lighting electrical installations of an industrial enterprise: 1 — device for introducing the working lighting network; 2 — devices for remote control of the operating lighting network; 3 — workshop panel; 4 — devices for automatic switching on of the emergency lighting network; 5 — device for entering the network for emergency lighting; 6 — step-down transformer of the power supply of the local lighting network; 7 — outgoing power lines of the lighting network.