Karting is the most popular and accessible to young people kind of motor sport. It is also interesting that card — an object of technical creativity. In addition, to gain initial driving skills on them much easier than on cars. You can start even from the age of nine. The simplicity and low cost of raw materials enable schools, Palaces of pioneers and the young technicians ‘ stations to build as many carts as you need for simultaneous teaching of a large group of guys. Also important is the advantage that these sports cars are cheap to operate and do not require storage spacious garages.
There is only one drawback: even with the standard mufflers card produce much more noise than cars. That’s why young kartingistov not always allowed to use for everyday training sites at schools or near homes.
This issue, and incidentally a number of other can be solved with the advent of the electric map.
Easy to control — two pedals and steering make electrocast besides convenient vehicle for children’s centres, where kids practice learn traffic rules. And the absence of exhaust gases allows to use maps in rooms — in large gymnasiums, indoor stadiums. This is especially good for guys living in the Northern regions of our country: a long winter does not hurt them to train all year round.
We offer description the electric chart, built in the experimental laboratory of micro cars (ELMA) Kursk Palace of pioneers. Here we used serial cards К5М. He removed the internal combustion engine with all systems and fuel tank, and instead put the motor and battery.
Perhaps the most difficult problem was the selection of a suitable and available motor. Students of the Kharkiv road Institute for the electric chart (see “M-K”, 1976, No. 8) used aircraft motor type P-2500. It is designed for a voltage of 24 V. In our opinion, this is not the best option.
Fig. 1. The graph of battery capacity from discharge current.
Fig. 2. Upgraded starter shaft.
Figure 3. Plate brush holder once finalized.
Fig. 4. Engine mounting bracket.
And not only because such a motor is difficult to get. When powered by a normal battery voltage of 12 V characteristics sharply deteriorate. So to ensure the 24V supply on the map, you need to install two 12-volt battery, inserting them sequentially. The only place on the map — at the back seat — allows you to set two acid battery type 6СТ68 capacity 68 A*h Battery with greater capacity do not fit.
Analyzed next. Serial connection of batteries, as you know, the battery capacity does not increase. Nominal it is only in the mode of ten-hour-discharge current is relatively small. You may want to increase it — and capacity-acid batteries drops sharply (Fig. 1). When the discharge current of 400 A (average current consumption of the motor R-2500) battery 6СТ68 it will be slightly more than 30%, or about 24 A*h the Most optimistic calculation allows in this case to rely only on 11-13 min of engine operation.
Using a 12-volt motor would it be possible to include the batteries in parallel. Then the total capacity will be 136. However, instead of them to the same place, you can install one battery 6ТСТ-182 (182 Ah). The Kursk electric chart is just such a battery.
A third year student with the selection of motor. 12-volt motors required power is most available for those wishing to make electrocars are automotive starters (see table).
In Kursk the electric chart used starter ST-8. At the same quiescent current (about 100 A), ratio of discharge current to the nominal capacity of the battery was more favorable (ip = 0,55 SN). The capacity of a given battery in this regard is 50% of nominal, that is 90 A*h. Then it is enough for almost an hour of continuous operation of the engine. And it’s at the same area occupied by the batteries on the map.
Car starter, as it is known, a DC motor with serial excitation. Therefore, the rotation speed of the shaft depends on the load and power consumption for different modes varies within a small range. These engines are used for microtransport, ceteris paribus provide greater vehicle range than engines with parallel excitation. This is because they “load” the battery evenly and therefore the best way to spend the energy present in it.
Before installing the card engine-the starter had to be refined. Instead of bronze-graphite bearings we installed ball. This took the covers with ball bearings from electric car GAZ-51. The rotor shaft of the starter is bored through to the dimensions specified in figure 2. On the cover side of the manifold set plate brush holder starter, pre-cut it in accordance with figure 3.
After the engine Assembly on the shaft put a spacer and the leading chain sprocket — motor, 12 teeth. The sprocket was also modified. In a pre-bored bore hole it is inserted a steel sleeve and welded by electric welding. For landing on the splined shaft of the starter sleeve into the cut slots. The sprocket on the shaft secured by a nut.
The engine is coupled with the frame using the bracket (Fig. 4). The chain tension — shift motor mounting bolts (Fig. 5).
Fig. 5. The engine on the frame.
Fig. 6. Frame for mounting the battery.
Fig. 7. Schematic wiring diagram.
In the process, the engine needs cooling. This applied to the electric fan from the heating system of the ZIL-157. He blows air at the corrugated core sleeve in the area of the engine manifold. The bandage covering the Windows starter, welded a short pipe from steel for connection sleeve.
The battery is mounted on the card using the frame from a steel angle 20 X 20 mm (Fig. 6). Their frame brackets are joined with bolts two bearings of the rear axle. This eliminates the load on the frame card.
Electrical schematic map shown in Fig. The motor is switched on remotely by means of the contactor K-250A, the voltage across the winding of which is supplied with the closure button VC-322 related to the throttle. Contactor is mounted on the seat back and isolated.
In the diagram, you can use a contactor if it provides the required commutation of the current consumed by the motor. The Ampacity of the button should correspond to the amount of current consumed by the coil of the contactor.
The fan includes a separate tumbler VK. It should work for all-time traffic map and even a short turn off the main engine. A demonstration race on electrocore young athletes Kursk Palace of pioneers first held during the summer competition in 1976. After petrol card the feeling of driving electric a bit unusual. Nothing should start, warm up, adjust.
Before the turn there is no need to use the brakes. Enough to let go of the throttle and speed falls off rapidly due to engine braking. On turns unlike conventional carts, there is no skidding of the rear wheels, as the considerable weight of the battery ensures reliable contact with the road.
The most unusual silence prevailing all over the drive.
The speed of our electrocast inferior to petrol: a maximum of 40 km/h. This is because the gear ratio of the main transmission (1 : 3) was chosen to obtain a good acceleration, but not the achievement records on the track.
Our design we do not consider it finished. Have yet to try other starters for use in an engine, increase the efficiency of the cooling system, to more precisely adjust the gear ratio. It would be nice to shift the center of gravity of the car forward.
But in this embodiment, electrocity you can apply for a training ride, And if the young kart clubs interested in electrocardiogram, will build several of these machines, soon will be possible to hold the first competition of the silent machines.