Do you have any idea how to make auto electrical test bench for testing a car alternator? Our article will help you to realize the idea, we will tell in details about the technologies of the bench assembly.
In order to find alternators’ failure, it is enough to make voltage regulator testing and tighten the belt. But, in the most cases, it is necessary to dismantle the alternator and install it on the bench for accurate diagnostics of the fault.
Alternator test on the handmade bench
The figure shows the bench for the alternator machine repair, then it is not difficult to assembleit.
The figure shows how to connect the alternator for further testing.
No. 1 voltmeter;
No. 2 tumbler switch;
No. 3 ammeter;
No. 4 battery;
No. 5 rheostat;
No. 6 alternator.
It is necessary to connect the electric motor on the handmade bench, adjust by a rheostat the voltage at the alternator output to 14V, the rotor speed should be up to 5 thousand rounds. After the alternator operating at the same rate, it is necessary to measure the recoil force of the current. When the recoil force is not less than 44 A, the alternator operation is good. If the figure is lower, it indicates possible problems with the winding, probably valves (diode bridge) are damaged, brushes wearis possible.
The alternator performance testing can be done by an oscilloscope. Rotate the alternator rotor with a frequency about two thousand rounds. If the stator and valve windings are in good conditions, the curve will look like a saw with equal teeth.
The figure shows an example, three options of the curve.
1. Alternator works normally;
2. Damaged valve;
3. Open circuit.
When the alternator is in a disassembled state, it is possible to diagnose the resistance of the excitation winding. The performance rate is 4 - 20 Ohm.
You can also check the winding using a signaling device. For testing, you need a battery and 12V control lamp. The battery wire is connected to the rotor; the second wire is connected to the slip ring assembly. The warning lamp during these actions should not light up. If it glows, it indicates the winding closure, that means it is necessary to replace the rotor, because it has failed.
When the alternator is in a disassembled state, it is possible to diagnose the stator winding. The stator is testedby connecting the control lamp to each winding output. If the lamp doesnt glow, it indicates the winding breakage. In this case, the stator or winding should be replaced.
Professional equipment for starters and alternators diagnostic
The presented scheme in the article is the simplest possible option. Students also can use it. In car service stations there are also handmade benches for starters and alternators testing, but service quality there is much lower, compared to the workshops that use professional diagnostic equipment.
Car service stations clients always pay attention to the equipment and tools used in the workshop. Therefore, the handmade bench is not attracted for drivers, rather, they will go to another service, where there is professional equipment.In addition, it is worth remembering that about 90% of carsmodel after 2010 year are equipped with the alternator of digital voltage regulators with the control signals transmission using the LIN protocol. In this case, it will be extremely difficult to check the alternator operation without an appropriate tester.
MSG Equipment offers professional equipment for testing the alternator and starter and repair. The company’s catalog presents the benches for the big car service stations and the testers for the small car services. Of course, the professional equipment has more opportunities than the equipment made with crude method.
MSG Equipment Multi-functional equipment increases the car service efficiency, helps to provide high-quality diagnostics and repair of starters and alternators.
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