DE29717480U1 - System for cooling speed-controlled drives - Google Patents

Description

1
Description

System for cooling speed-controlled drives

The invention relates to a system for cooling speed-controlled drives, which have converter-fed three-phase motors or DC drives as shunt machines fed via thyristor devices, whereby a controller and power electronics part is present.

Modern, high-quality drives are now all designed with speed control. Such drives are either constructed as converter-fed three-phase motors or as shunt-wound machines fed with direct current via thyristor devices. Such drives have a wide range of applications in general technology, particularly in the basic materials industry.

The latter applies in particular to the crane systems used there. For example, so-called charging cranes are needed in the steel industry for transporting pig iron ladles, among other things as well as for the actual casting process.

Especially in heavy industry, the atmosphere in the production halls is usually characterized by strong temperature fluctuations, with temperatures of up to 80 ^° C being able to occur. In iron and steel works, there is also locally significant radiant heat, for example from pig iron pans or similar. There is also a lot of dust in such halls, which can be conductive, for example in the form of graphite dust. In such atmospheres, which may also be chemically aggressive, the electrical and electronic supply components for the drives in particular must therefore be protected in the production halls. As already mentioned, this applies especially to iron and steel works, but also in the chemical industry.

GR 96 G 8607 EN 01 ... _## »» ....

The object of the invention is therefore to provide a system for cooling speed-controlled drives, in particular for use in the basic materials industry, with suitable means for the controller and power electronics part, so that operation in the aggressive atmosphere is possible.

The object is achieved according to the invention in that the controller and power electronics part is housed in a closed cabinet and is operated with circulating cooling. Preferably, an air/refrigerant heat exchanger is housed in a separate cabinet and is exposed to an air flow. The air flow is regulated in particular by a fan with an adjustable speed.

The actual refrigeration machine, however, is located outside the room for the controller and power electronics part.

The invention is preferably used in charging and/or casting cranes in steelworks, with the closed cabinet serving as a refrigerator being advantageously housed in the crane girder of the charging and/or casting crane. Such cranes always have drives that are operated with asynchronous motors, as well as additional main drives that are designed to be fully redundant. The undercarriage drives are usually designed in such a way that individual groups can maintain operation completely with reduced acceleration and braking times.

The three-phase motors used are fed by converters. The drives are equipped with voltage intermediate circuit converters using fully digital technology. This achieves a dynamic comparable to that of a direct current drive. This enables smooth acceleration and deceleration, maximum positioning

GR 96 G 8607 EN 01 ^ ,

accuracy for all drives, so that the crane reaches the most important positions, such as picking up the ladles, taking pig iron from the mixers and emptying it into the converter, in the shortest possible time. To ensure this, according to the invention, all electronic components are arranged at a suitable location on the crane, protected from undesirable operating influences.

Further details and advantages of the invention emerge from the following description of embodiments based on the drawing in conjunction with further subclaims.

FIG 1 shows a schematic representation of a steelworks gantry crane in which the power and electronics part for the drives is housed in the crane girder, and

FIG 2 shows the principle diagram of the circulating-cooled converter/DC feeds used.

Figure 1 shows a casting crane, as is usually found in steelworks for charging casting ladles or the like. A movable crane girder 2 is placed lengthways in the casting hall on steel supports 1 or 1' with cross beams 10 or 10', to which a control cabin 3 is attached on one side and a movable trolley with lifting gear 4 on the other. A casting ladle 5 is suspended from the lifting gear 4 for clarity.

Other loads often have to be lifted and transported within the casting hall. For this purpose, a trolley (not shown in Figure 1) with a second lifting device is usually available.

The principle diagram according to Figure 2 shows the crane girder from Figure 1. Within the crane girder 2, closed units 20 and 30 are shown as barriers,

GR 96 G 8607 EN 01

• · · &idgr;

which accommodate the sensitive controller and power electronics components and protect them from the aggressive atmosphere of the steelworks.

In detail, a controller and power electronics part is present as a converter 23, to which an inverter 22 on the one hand and a feed-in/feedback unit 21 on the other hand are assigned. The entire controller and power electronics part is housed in the cabinet 20 and is operated using circulating cooling. An air/refrigerant heat exchanger is housed in another part, the so-called refrigerator 26. The air flow is regulated by a fan 25 with adjustable speed. This keeps the electronics and power part 21 at an optimal operating temperature.

A refrigeration machine 40 must be present to operate the system. A fan 27 and an air-refrigerant heat exchanger 28 are also housed in the cabinet 30 connected in parallel to the cabinet 20. The circulating air is blown into the hall from here. The entire unit 31 is housed outside the room for the electronic units in order to keep the waste heat away from the electrical area. The refrigeration machine 40 is designed for an ambient temperature of up to 90 ⁰ C, with the condensation temperature of the low-pressure refrigerant used being 105 to 110 ⁰ C.

By separating the internal circuit from the external atmosphere, the IP65 protection class required in electrical engineering and defined in detail is guaranteed. This makes an important contribution to safety, especially in steelworks.

Claims (6)

GR 96 G 8607 DE 01 ♦·■♦· ·· Protection claims 1. System for cooling speed-controlled drives which have converter-fed three-phase motors or direct current drives as shunt machines fed via thyristor devices, for which a controller and power electronics part is provided, characterized in that the controller and power electronics part (21, 22) is housed in a closed cabinet (20) and is operated with circulating cooling. 2. System according to claim 1, characterized in that at least one air/refrigerant heat exchanger {25, 28) is arranged in a separate cabinet (20, 30) and is exposed to an air flow. 3. System according to claim 2, characterized in that the air flow is regulated by a fan (25, 27) with adjustable speed. 4. System according to one of the preceding claims, characterized in that the refrigeration machine (40) is housed outside the cabinet (20) for the controller and power electronics part (21). 5. Installation according to one of the preceding claims, characterized in the application in charging and/or casting cranes (1-5) in the steel industry. 6. Installation according to claim 5, characterized in that the closed cabinet (20, 30) is housed in the crane girder (2) of the charging and/or casting crane (1-5).