If you suspect a malfunction in the alternator, take the following measurements before removal:
1) check the charging current wire:
- Disconnect the negative wire from the battery and disconnect the connector from the back of the generator or unscrew the wire;
- reconnect the wire to the battery and turn on the ignition;
- Connect a voltmeter to «mass» and any terminal of the multi-pin plug connector, when connected to all terminals, the voltmeter should show a value approximately equal to the battery voltage, otherwise the generator or voltage regulator is faulty;
![](https://www.fordbook.ru/img/mondeo/5117.jpg)
Pic. 286. Checking the return of current by the generator
2) current output (to check the adjusting resistor of 30 A, in addition to the ammeter, you must also have a voltmeter, they are necessary to create the electrical circuit shown in fig. 286):
- turn on the headlights and the heater electric motor;
- set the motor speed to 3000 min-1 and change the resistance to increase the current consumption;
- the rated current of the three-phase current generator must be reached (70A), and at the same time the voltage should not fall below 13 V;
- turn off the ignition and consumers and disconnect the measuring devices;
3) voltage drop test «positive» parts of the charging current circuit:
![](https://www.fordbook.ru/img/mondeo/5118.jpg)
Pic. 287. Checking the voltage drop in «positive» parts of the charging current circuit
- create an electrical circuit as shown in fig. 287;
- turn on the headlights, start the engine and measure the voltage drop;
- bring the engine speed up to 3000 min-1 and read the voltmeter reading. If the measured voltage exceeds 0.5 V, then in «positive» parts of the generator high resistance, which should be eliminated;
- turn off the ignition and headlights;
4) voltage drop test «negative» parts of the charging current circuit:
![](https://www.fordbook.ru/img/mondeo/5119.jpg)
Pic. 288. Checking the voltage drop in «negative» parts of the charging current circuit
- create an electrical circuit as shown in fig. 288, start the engine, turn on the headlights and measure the voltage drop;
- bring the engine speed up to 3000 min-1 and read the voltmeter reading. If the measured voltage exceeds 0.25 V, then in «negative» parts of the generator high resistance, which should be eliminated;
- switch off ignition and headlights, disconnect control wires and the voltmeter;
5) checking the regulator based on the regulation voltage:
![](https://www.fordbook.ru/img/mondeo/5120.jpg)
Pic. 289. Checking the regulator based on the regulation voltage
- connect the voltmeter and ammeter according to fig. 289;
- start the engine and measure the regulation voltage;
- bring the engine speed up to 3000 min-1 and watch the ammeter. As soon as the value shown by the ammeter drops to a value within 3-5 V, take a reading on the voltmeter, the voltage shown should be in the range of 13.7-14.6 V. If the value on the voltmeter is outside the specified interval, the voltage regulator is faulty.
Visitor comments