Hoist Motor Carbon Brush Holder For Tower Crane
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Products Specification
Hoist Motor Carbon Brush Holder For Tower Crane
Hoist Motor Carbon Brush
Hoist Motor Carbon Brush Holder
51.5kw hoist motor
40.5kw hoist motor
| Hoist Carbon brush, as a sliding contact, in many electrical equipment has been widely used. Carbon brush in the product application materials are mainly graphite, dipped in graphite, metal (including copper, silver) graphite. |
| The look of the carbon brush is like a rubber pen with a pencil, and there is a wire on the top. The volume is very small. Carbon brushes as a sliding contact, in many electrical equipment has been widely used. Product materials are mainly electro-graphite, dipped in graphite, metal (including copper, silver) graphite. |
Hoist Motor Carbon Brush Holder For Tower Crane
Hoist Motor Carbon Brush
Hoist Motor Carbon Brush Holder
51.5kw hoist motor
40.5kw hoist motor
Tower Crane Knowledge sharing：
Analysis of reasons and treatment of frequent trip of electric leakage protectors at construction site
2. There is no effective second or third level leakage protection within the protection area
The upper stage leakage protector in the switch box is the main protection of the electric equipment. If the upper stage leakage protector is not installed, damaged or improperly selected, it may cause the upper leakage protector to frequently trip. For example, the lighting part of the construction site is quite confusing and there are many problems: the site lighting line is often re-laid with the change of the construction site, and there are many chaotic hanging phenomena.
The wire insulation is not very good, and it often leaks electricity; Although the on-site office lighting line is relatively fixed, it is generally relatively low, easy to reach, and there are also some socket loops. In many cases, no leakage protection is installed, especially when it is dark and requires lighting. It often causes frequent jumps of the total leakage protector.
There are many mobile devices on the construction site, such as vibrators, hand drills, small cutting machines, ramming machines, and small welding machines. Sometimes these devices are used without access to the switch box, which also increases the total leakage protection.
The chance of frequent trip. Only by forming an effective second or third level leakage protection mode in each protection area can the frequent trip of the leakage protection device be effectively reduced.
Hoist Motor Carbon Brush Holder For Tower Crane
Hoist Motor Carbon Brush
Hoist Motor Carbon Brush Holder
51.5kw hoist motor
40.5kw hoist motor
3. The leakage protector itself has certain limitations
(1) The current leakage protectors, whether electromagnetic or electronic, use magnetic induction voltage Transformers to pick up leakage currents in the main circuit of electric equipment, and three-phase or three-phase four-wire can not be completely balanced in the magnetic ring.
There are more two-phase or single-phase loads such as welding machines on the construction site. The three-phase current can not be completely balanced. It will even be very different. At large currents or high overvoltage, there will be a high magnetic conductivity.
A certain electromotive force is induced in the magnetic ring. This electromotive force is large enough to cause the leakage protector to trip. Moreover, because the larger the rated current, the larger the magnetic leakage protection device uses a relatively large magnetic ring, the resulting magnetic leakage flux is also relatively large.
the leakage current must overcome the magnetization of the magnetic ring itself, resulting in the actual use of the leakage protection device. The larger the rated current, the lower the sensitivity, The greater the rate of mismovement or rejection.
(2) There is an uncertain area between the rated leakage action current and the rated leakage non-action current of the leakage protection device. When the leakage current of the leakage protection device fluctuates in this area, it may cause the leakage protection device to have no regular trip.
Hoist Motor Carbon Brush Holder For Tower Crane
Hoist Motor Carbon Brush
Hoist Motor Carbon Brush Holder
51.5kw hoist motor
40.5kw hoist motor
4. Unreasonable type selection of leakage protector
(1) The rated leakage current used in the switch box is more than 30mA or more than twice the rated current of the power supply device, or a leakage protection device with a delay type is selected. Due to the increase of the rated leakage action current or the decrease of the protection sensitivity, in the event of a leakage failure, the last leakage protection device has no action, and the upper leakage protection device may act.
(2) Some random use loads do not have dedicated switch boxes, such as type I, type II electric hammers, electric drills, small cutting machines, and other hand-held electric tools. After connecting a leakage protector with a large rated current, in case of leakage or failure, The upper level leakage protector may refuse to move, or it may trip at the same time as the upper level leakage protector.
(3) There are many welding machines on the construction site.
The leakage protection device of the welding machine is selected according to the rated current of the welding machine. The large current at the welding of the welding machine may cause the leakage protection device to trip. This is part of the welding machine.
The reason for the leakage protection device trip. For this kind of electric equipment, electromagnetic leakage protectors that are not sensitive to overvoltage and overcurrent should be selected. Or use an electronic leakage protector that is 1.5-2 times larger than the electric welder's rated current, but as an upper stage leakage protection, the rated leakage action current should not be greater than 30mA.
(4) The tower crane is a large construction equipment at the construction site. There are multiple Motors. Although the start-up process uses Y-Δstart and the rotor loop series resistance start, which reduces the starting current, there is still a large starting current. Y-Δstarting and motor speed change will randomly produce a certain amount of overvoltage.
Tower hanging distribution box and distribution line in the high air, long years of sun and rain, insulation inevitably has certain damage, resulting in a corresponding increase in leakage current. All of these factors may cause frequent trip of the leakage protector of the tower crane.
When considering the use of electronic leakage protectors, its rated current should be amplified by 1.5-2 times appropriately to reduce the sensitivity of the leakage protectors themselves and reduce the probability of frequent trips.
Hoist Motor Carbon Brush Holder For Tower Crane
Hoist Motor Carbon Brush
Hoist Motor Carbon Brush Holder
51.5kw hoist motor
40.5kw hoist motor
(5) The superior leakage current protection of the upper stage leakage protection is too small for rated leakage action current and rated leakage non-action current, and relatively large normal leakage current may be present on the distribution line after the leakage protection device is not considered.
