In principle, each hood like a vacuum cleaner (the principle of action), but performs other tasks. Power vacuum continuously adjustable, allowing you to select the desired mode. In the kitchen hood speed circuit, when the rate replaced, without a smooth transition, the electrical circuit is different. For smooth adjustment of frequently used triacs, abrupt change easier to produce switched windings. Regardless of the stretching device, in both cases applies amplitude control, therefore does not exclude the existence schemes or keys thyristor inverter control. In the latter case, the device extracts the kitchen will cost a pretty penny.
engine's type
Induction motor dominates. As used simplified embodiment provides the highest sound pressure level (noise). Quiet induction motors are too complicated, which is why rising price of the device. Sometimes the design of copies floor fan. Low power hoods equipped with asynchronous motors, where speed changes switched windings.
What it consists of kitchen hood
The parameters include the performance of hoods. This superior quality. Extractor hood, regardless of the complexity consists of two branches:
- Lighting. There are surprisingly rare LEDs, the authors tend to think that the case of the need to accurately position the voltage for these devices. Combustion LEDs include one direction, therefore, the next half-cycle is lost. Scheme obtained difficult. Flickering of lighting fixtures, is known to lead to fainting, even if invisible to the human eye. Incandescent bulbs and halogen are common.
- The second branch of the cooker hood goes into the engine. There are fuses - if available, other protection devices. Induction motors shaded pole sin low torque at the start mechanism may rattle. In designs with the auxiliary winding in the electrical circuit to produce capacitors pose similarity second phase. The unit degenerates into a floor fan. Split poles determined visually by the presence of oblique thick copper windings magnetically recessed.
Induction motor shaded pole
Fan put tangential. We get the hang of it the maximum load without fear of overloading. The axial pressure immediately falls on the blade is passed along to the engine, then the bearings. Increases friction, wear and tear increases. Later begins the heating device, which often leads to an accelerated exit of the cooker hood down. Tangential fans in this sense is best: the load is transferred to the electric field, then the coils.
The principle of operation of the cooker hood is simple: air enters the center of the flywheel, and then pushed to the periphery of the power of the blades. In some motors is difficult to find a way out from the structure. It is possible that you have to disassemble the cabinet to understand, or to start the engine. Beware in the latter case an electric shock. The serviceable engine should call. Feature kitchen hoods in two lobes, the fact contains the fundamental difference from the vacuum cleaner. Suction force sacrificed for the sake of performance.
Induction motor overheating is not afraid, but a bona fide manufacturer usually supplies the thermal fuses devices. Mounted on bracket to the body or seated between the coils (on top or beneath the fabric). According to a characteristic feature and can not determine the type, at the West made sign products.
The foregoing also applies to transformers and motors (all winding protecting from overheating). Thus, the engine together with the body in the kitchen hood reminiscent of a double volute. Between the shells engine. Air enters from two sides, and leaves behind (to reduce the vertical size of the body).
Species extracts are similar as twins, and note the differences. We describe how to construct the productive model, but cheap supplied with axial fans. Noisy, stupid, bad draw air. Simply slit with blades inside. Passage closed lattice filter even absent. Motor clogged with fat in a matter of weeks. We believe that the excessive contamination of the heat will simply fire fat layer.
The insides of kitchen hood
Axial fan is not the best option for the kitchen hood, but cheap. It is placed inside an induction motor for a simple reason: collecting noise and requires the inclusion of a number of elements in a cheap design inappropriate (e.g., noise absorbers). Attachments to include a brush, adding weight and complexity to the service. An additional reason - a high level of vibrations.
The result is within the asynchronous motor with squirrel cage type "squirrel cage". At the initial time does not require high starting point, let us assume that the tweaks in this respect is not taken.
The stator poles are generated by two coils, connected in the correct sequence and opposing each other. The field induced in the rotor from the stationary part of the engine. Wires are not isolated from the drum, a small current. Able to illuminate only the stator. Here austere voltage is 220 V (50 Hz) to acquire a good line filter for connection device. This will protect the household equipment from random noise. Otherwise (multimedia) cinemas (VCRs) will be under some level of threat of the drops generated by starting and stopping the induction motor. As is known, in this regard, the current consumption can be ten times higher than the rated.
hoods operating principle is simple:
- Stuck a fork into an electrical outlet.
- Press up schematic mnemonics blades.
- Induction motor starts to run.
As is known, electric hobs grounded, kitchen hood, too, relies ground. The engine is assembled on the circuit with friction bearings. Balls, as such, no. Instead, they are curved washers that were put on the shaft, provide the necessary elasticity. The rotor is mounted between two clamps are tightened on the screws, the axis goes back and forth to allow relative ease of construction of rotation. As a result, the rotor blades leaving a little upwards. Recall that the engine looks down. It turns out that at the start of the blades are raised (lowered then formed knock). From the air flow density balance point is dependent on the length of the working axis.
Simply put, the axis travels back and forth. extraction device requires constant lubrication. Recall that the gases passing weak lattice, even in the first approximation can not be regarded as a filter, go to the motor, which is located in front of the blades. As a result, the windings are cooled (air burning stoves) extending flow. But soot, grease settle here without fail that proved dismantling device. Drip oil on the bearings have to disassemble the motor (disconnect the power cord from the mains).
- Unscrewed the bracket screws.
- The rotor is removed.
- Lubricated.
The assembly requires special attention: the slightest bias in favor of any of the screws immediately leads to the seizure of the rotor, which drastically reduce efficiency, increase uselessly spending power. The motor will start to warm up the shock. Tightening the screws, check carefully whether the movable axis lost. Verification is performed after assembly. Shaft rotates completely silent.
Kitchen hood efficiency is low as productivity. Pay particular attention to the lattice. If the input has the meaning of the grease filter, is installed near the blade makes it difficult to move air only. This direct reduction of the already low productivity. Remember, each turn 90 degrees duct channel reduces efficiency of 10%. Specifications extracts change during installation. The result depends on the proper installation, completion feasible and necessary service equipment. drawing operation depends on the skillful hands of the owner.
