motion-sensor

The sensors also known as motion detectors, allow automatic feeding of electrical equipment for a fixed period (adjustable), mostly in lighting and in places of passage (corridors, stairs) or outdoors. It is also common to find it for reasons of hygiene in the bathroom, allowing the ignition without physical contact.

The sensors offer many possibilities, such as controlling the opening of an automatic gate, preventing an intrusion, etc.. We will deal in this article, only the basics of using a presence detector 3 son. Other articles will follow to more advanced applications such as adding controls to stop or forced march, a combination of clock ...
The detectors have to operate three son needs a permanent supply (phase and neutral). Although it is tiny in proportion, we can therefore say that they consume electricity at all times (lights out) as opposed to via the ignition switch classics.
The detector therefore has two terminals for the power supply (L and N), and a third called "back light" (L1), which will connect the devices to be controlled. When a presence is detected, an internal contact connects the phase of the diet (L) to the third terminal, the output (L1).

L1 * The term is confusing because the lette L is generally reserved for the stage. The L1 is just a reminder that it is indeed a phase when the device closes the internal contact, and so there is risk of short-circuit if there was a neutral connected.
 
Caution

There are sensors that do not require the presence of neutral (2 son), but they cause problems with the majority of energy saving lamps as incandescent bulbs will soon be withdrawn. CFLs also pose problems which this time concerns all modes of command "timed", requiring a minimum operating to illuminate and see their life significantly compromised by short-circuit and over again.

Wiring diagram of a presence detector

The internal contact to the device is shown here between terminals L and L1, showing that the detector acts as a switch-type single ignition . Once a presence is detected, the contact closes for a period of time, allowing the power of the lamps.

scheme developed (bypass)

 

Example of connection that can help you to connect your lighting circuits. The distribution of the son is by Wago terminal type or dominoes usually in boxes.

More detectors for the same circuit

It is possible to combine several sensors for food from the same circuit. It should just connect (bridge) the phase, neutral and the return of light between the different detectors.
The number of sensors is unlimited, while the number of lamps is limited to eight, some of the type of control used.

For more power ...

Contacts internal sensors are limited in switching capacity. In other words they are not designed to withstand high power. The maximum power in Watts (W) admitted on the detectors is shown, and if your needs are more important you must supply the devices through a relay called a "contactor".
The switch acts as an intermediary between the sensor and devices to be powered. It consists of an electromagnetic coil and contacts. When the coil is energized (terminals A1 and A2), the internal switch contacts are closed in turn act as switches by which we will take the power of our devices.

The contactors are available in several ranges of voltage and current, and types of contacts.

- Ensure that the breaking capacity (ability to open a contact for a given intensity) of the contactor is suitable for the selected circuit breaker and is the power of the downstream devices.
- Contacts are used by the NO (Normally Open), normally open. Conversely contact NC (Normally Closed) are closed at rest and open when the coil is energized. Some switches can associate contacts NO and NC contacts.
- The voltage of the contactor coil must be designed to support here from 230V AC. There are switches for all coming out of AC voltage as current.
- The voltage contacts are also important because that may differ from the supply voltage of the coil. Ensure they support the operating voltage concerned.

As shown in this diagram, two guards are then required. We have a circuit breaker to protect the control unit (detector + contactor coil) and another for the power (power contacts and devices). For clarity of the control section and power section were drawn in different colors. In practice they will have the same color.
We might as well use this method of wiring to power anything other than lighting fixtures, in which case it will fit for the power circuit breaker and the section used son.

Supply several lighting circuits from a single detector

NF C 15-100 authorizes the cutting of non-neutral light fixtures (lights and only!), As is the case with conventional switches, off on the scheme before we also increased the neutral the contactor.
It is possible as illustrated by the following scheme to do to get our phase, making the first contact for food available in another circuit.

For convenience the second circuit is differential, this time by dotted lines.
This wiring does not apply again for the case of two lighting circuits, switching off the neutral is required in all other cases!
The solution presented below shows how power circuits of different types (cut from neutral) with a contactor circuit, but it is also possible to replace the bipolar switch (2 contacts) above by a switch pole (4 contact ), leaving two circuit contacts. So a 3 pole contactor contacts would also supply a lighting circuit without breaking the circuit neutral and another with a cut of the neutral.

Detector and circuits of different types

Let us now use a single command, by the detector, to power various electrical circuits. Electrical outlets on the following diagram symbolize all kinds of devices provided that section, circuit breaker and the breaking capacity of the contactor are suitable partner.

We have a circuit breaker for control 2A, 10A circuit breaker for the lighting and finally a 16A circuit for our catch. Suppose a decision served watering the garden in case of intrusion of an animal enemy (it would be better then to associate a clock and a switch to avoid some unpleasantness), etc.. What we want as long as you do not kill anyone or anything with your system!