To put the engine into action, it must be started. For this, a starter is provided in the vehicle device. KamAZ Euro-3 is also equipped with it. The mechanism is of various types. Well, let's look at how the KamAZ starter is designed, how it works and what technical characteristics it has.
Varieties
There are several types of these mechanisms:
KamAZ starter belongs to the first type of device. This mechanism is the most powerful, since here the transmission of torque from the anchor to the gear is carried out by the gearbox. Such starters have not only high power, but also a good starting torque. They also have a long service life. These types of starters are used on 90 percent of modern cars.
As for gearless elements, they act as follows. After the voltage arrives at the electromagnetic switch, the bendix gear moves and engages the flywheel crown. Current flows to the anchor. There is a rotation. Gear with shaft combined thanks to freewheel. After a successful engine start, this connection loosens. The current supply stops and the gear returns to its original position. Due to low efficiency and low maintainability, gearless elements are practically not used in the automotive industry.
Device
Structurally, the KamAZ starter is an electric motor with a traction relay and a mechanical drive. This mechanism is installed on the flywheel housing (located on the left side of the engine). It is mounted on three bolts with studs.
The mechanism is based on a 4-pole electric motor with series excitation. Also, the following elements are included in the starter design:
- Drive shaft.
- Anchor.
- Back and front cover.
- Collector.
- Brush assembly.
- Solenoid Relay for KamAZ Starter.
- Field winding.
All this is combined in a metal case. Outwardly, the KamAZ starter looks like the one shown in the photo below.
The body is made of mild steel. It serves as a magnetic circuit where the cores are attached. The case is closed by covers. The back hides the brush assembly. Front - drive mechanism. The exciting winding is divided into parallel branches, in which series-connected coils are used. A copper wire with a rectangular cross section is used as a winding. One end is connected to positive brushes, and the second to the insulated terminal of the housing.
All coils are impregnated with a special varnish and additionally braided with cotton tape. The turns are insulated with cable paper.
Anchor
As for the anchor, it includes the following elements:
- Shaft with corrector.
- Winding.
- Core.
The latter is made from sheets of electrical steel. The collector is designed to maintain constant torque. The winding is wave type. 2 wires are laid in the grooves of the core.
Moreover, their turns are isolated from the core. The end of the wires is laid in the slot of the copper plate of the collector and soldered.
Brushes
This assembly provides voltage to the collector plates. Brush holders are a dielectric holder with metal inserts. The latter are inside the brushes. The contacts are welded to the pole plates by spot welding. This element is the tail of the field winding. The brushes themselves are made of an alloy of lead, copper and graphite. Additionally, tin is added to the composition. Such an alloy prevents voltage drop in the winding and reduces collector wear.
How does it work
After a turn of the ignition key, voltage is supplied to an additional (PC-530) starter relay. KamAZ remains standing still. After the voltage exceeds the 8 V bar, the traction relay is switched on.
The mechanism forcibly connects the drive gear to the flywheel ring gear. Also at this time, the starter power contacts close. The anchor begins to rotate. Torque is transmitted to the flywheel. After the engine has started, the gear automatically disengages.
Specifications
On KamAZ trucks, the St-142b starter is installed. It has the following characteristics:
- Voltage is 24 Volts.
- Rated power - 7.7 kW or 10.5 horsepower.
- The voltage for activating the solenoid relay is 8 volts.
- The pressure of the brush springs is 2 kgf.
- The height of the brushes is 19-20 millimeters.
- The current strength is 130 amperes.
- The idle speed of the anchor is 5.5 thousand per minute.
Starter (KamAZ): price
The market offers a lot of both new and remanufactured starters.
What is the price for a starter (KamAZ)? The device brand St-142b can be purchased at a price of 4.5 to 13 thousand rubles.
Malfunctions and starter repair
KamAZ is a very repairable truck. In the event of malfunctions, you can fix the breakdown yourself. Consider the typical problems with the St-142b starter:
- When the ignition is turned on, the device does not work. In this case, it is necessary to check the winding of the traction relay. There may be a short circuit or open circuit. Depending on the nature of the breakdown, a retractor needs to be replaced. Also, the cause of damage can be the lack of contact between the brushes and the collector. In this case, check the pressure of the brush springs. If it is less than 1.8 kgf, the element is replaced with a new one.
- The traction relay does not work. It is necessary to check the winding of the auxiliary relay and verify the integrity of the retractor winding. Also check the reliability of the contact in the circuit and all connections.
- When the starter is turned on, characteristic clicks of an additional relay appear. The drive gear sticks to the flywheel crown. Perhaps the reason lies in the incorrectly configured moment of contact closure of the traction relay. How to fix this? The gap is set between the gear and the thrust washer. Next, check the operation of the mechanism. If symptoms recur, the end of the starter drive or flywheel teeth may have been clogged. There are several ways to fix the problem. The first is to restore the teeth using surfacing. The second is to replace the flywheel crown or drive gear. The third method involves cleaning the irregularities on the teeth.
- During operation, the anchor turns, but does not interact with the flywheel. The crankshaft does not spin. In this situation, it is required to check the integrity of the teeth of the flywheel, as well as the drive gear. Re-adjust the starter as well.
Conclusion
So, we found out what the KamAZ starter is, what technical characteristics and malfunctions it has. As you can see, this is a very complex mechanism. If a malfunction occurs (or simply symptoms), an urgent repair is required. Otherwise, you will not be able to start the engine.