A limit switch with a roller, the photo of which will be presented below, is a rather simple, but very effective device that is used very often. Some people call this device a trailer.
Fixture Overview
The main task of any device in this category is to transmit a control signal at a time when the actuator reaches its extreme or fixed position, set manually. Because of this purpose, some call this device a limit switch. For example, a vivid example of the use of a limit switch with a roller is the work of a crane or crane beams. When the load is lifted to a certain height, a signal will come to the electromechanical device, which, in turn, will disconnect the electrical part from the power supply. Thus, an automatic shutdown occurs.
By their principle of operation, all devices in this category are very similar to the most ordinary switches, the main difference is only that the disconnection does not occur when a person presses a button, but automatically, from an electric pulse (signal).
Varieties of circuit breakers
Currently, there are three main categories to which all types of these devices belong:
- The first category is mechanical. This also includes limit switches with a roller. Such devices do not work due to an electrical impulse, but from a mechanical action on a lever or a wheel. When a force arises on these elements, either shorting or opening of the contacts occurs. In these cases, two types of signal can be given: control or signaling.
- The second category is non-contact. Such devices work at a time when an object that has previously been configured to switch with a switch approaches them at a certain distance.
- The third category is magnetic. As the name of the group, they work with a magnet. That is, when a substance with magnetic properties approaches them at a certain distance, a short circuit or opening occurs.
Device usage
If we talk about the scope of application of limit switches with a roller and other types, then it is important to note that each of them is used in its field, since they are all different in their design.
However, there are conditionally two categories of units in which these devices are operated:
- The first group is protective devices. Naturally, the main purpose of such devices is to protect either workers or equipment from emergency situations. A rather striking example of such work is an elevator that lowers the miners into the mine. Until the doors close, the elevator will not begin to move. In addition, it is in such situations that the use of limit switches with a roller is most clearly seen.
- The second group is functional units. The operation of devices in this category is configured to control the electrical mechanisms for turning on or off the light. The simplest and most understandable example is the light in the refrigerator when opening / closing doors.
Device device
Despite the fact that electromechanical devices are divided into three categories, they all have several basic details related to the design.
The first common part of roller limit switches and all other devices is the housing. It is performed in just two types. Either from a material that is a dielectric, that is, it does not conduct electricity, or, conversely, from a substance with good current conductivity.
The second part is a moving part. It is available in almost all devices, and its main purpose is to influence the contact group at the moment when pressure is exerted on it. I do not have such a part, only contactless units.
The last common detail for all types is the contact part. Most often, locking and opening elements are contained here.
A little tip: when choosing such devices, it is very important to pay attention to the operating current and voltage, since the life of the device will depend on these indicators.
Overview of mechanical models
The scope of use of mechanical devices depends on their design, and therefore there are several options: limit switch with roller, button, lever.
The main areas of application for roller and other types of devices are metallurgy, construction and mechanical engineering. Most often they are equipped with such parts as a group of contacts of the closing and opening type, as well as rubber seals.
A small addition to this category are microswitches. The principle of operation of these devices is similar to conventional switches. The main difference from other types is that the working current is much less, and the working stroke of the elements is reduced to millimeters. Because of this, an additional lever equipped with a small roller is used in their design. Because of this feature, installation and configuration require a thorough approach. We can say that these are limit switches with rollers, but in a reduced form.
LOVATO company
There are many companies that manufacture and assemble such devices. LOVATO ELECTRIC has become quite popular and famous among them.
The limit switch with LOVATO roller differs from the others in that, like other models of this company, it has a rather simple and clear design. This makes it easy and quick to mount and install the device. The simple design also allows you to quickly and easily configure settings. The reliability of such devices is guaranteed by the manufacturer. The housings of these devices are completely removable, and a threaded screw is used for their fasteners. Also, the models were equipped with new bayonet heads, which allows you to remove and replace working heads without any problems without the use of additional tools or devices. The rotation of the heads of these devices occurs in the axial plane at an angle of 45 °. There are also additional units that are removable.
Limit switch with roller Telemecanique xck p
This company also produces roller and other models of limit switches. In addition to the fact that ordinary roller-type devices of instant action are manufactured with the necessary force to operate at 0-13 Nm, switches with roller levers and plungers are also manufactured. The main difference between each type of these electromechanical devices is that they have different actuation forces. For example, for devices with roller levers, this figure is from 8 to 24 Nm.
Another of the rather popular devices is the limit switch with a YL 5200 roller. It is most often used at large industrial enterprises during the operation of conveyor and other engineering equipment.