Disconnecting a small voltage source from a coil (inductor) causes a larger, often a much larger, reverse voltage spike due to the collapse of the magnetic field in the inductor coupled with the sudden absence of a current path to dissipate the electromagnetic energy.
An inductor resists a change in current. The equation for an inductor is ...
di/dt = V/L
... which means that the rate of change of current is proportional to voltage and inversely proportional to inductance.
If you have a current established in an inductor, and then suddenly open the circuit, the inductor will attempt to maintain that current. It can't, however, because the circuit is open, having large resistance. By ohm's law, voltage is resistance times current. If you keep current constant, and make resistance large, then voltage has to also be large.
In the theoretical case of an ideal inductor in an ideal circuit, the voltage spike would have infinite voltage. In practice, we see spikes of several hundred to several thousand volts, depending on the particular cirsumstances.
the large collapse in the magnetic field
The large collapse in the magnect field.
A battery disconnection switch is a special switch that is specifically designed to be able to carry a large or heavy electrical current. It allows you to turn off the voltage without the use of tools.
A "battery disconnect" is nothing more than a special SWITCH designed and manufactured to be able to carry very large [heavy] electrical current. The one with which I'm familiar mounts on the positive battery terminal after the cable has been removed, and then the cable connector is attached to the output terminal of the disconnect switch. This switch allows one to totally and completely "kill" the battery voltage to the auto circuits, without having to use a wrench to loosen a battery terminal clamp and manually "wrestle" it from the terminal.
The engine computer is the voltage regulator. It is the large black box behind the battery.
yes, old and new battery should have same voltage rating. Battery type shud match only capacity may be large.
It is a meter with a high wattage resistor connected parallel with the meter that drains power from the battery while it is measuring the voltage it is used to test the condition of the battery if the condition is good there will not be a large voltage drop while testing the battery
The main power producers in an electrical system are the battery and alternator. The alternator puts 14 volts of alternating current into the electrical system and resistors. The resistors only allow a fraction of the AC voltage produced to reach the systems' sensitive components
Generally the solution to these problems is don't disconnect the battery from the car. In order to change you battery you need to connect a small 12 volt battery to the terminals before you disconnect the car battery. It need not be a large battery since the drain will be minimal and the time short. A set of flashlight batteries works fine. Mercedes are particularily difficult because you loose the radio among other things if you disconnect the battery. You must get a dealer to reset it. This negates anything you save by installing your own battery. Note a battery charger also works.
Transformers only work on a.c. This is because it's necessary to have a changing primary current in order to induce a voltage into the secondary winding.If you connect a battery across a transformer, it will not work. Furthermore, if the voltage of the battery matches that of the rated primary voltage, the resulting very large d.c. current is likely to overheat the primary windings and even burn it out.
# Disconnect negative battery cable # Raise truck and support it # Disconnect the large cable from the terminal on the starter # Remove 4 bolts or nuts securing the starter and remove the starter from engine
You should locate and test the solenoid. Most have three connections. There is a large cable from the battery to the solenoid, from the solenoid to the starter and from the start switch to the solenoid. The power terminals to the battery and the starter are large and have large cables. The starter switch connection is much smaller. Turning the key to 'start' provides a low current voltage to the solenoid causing the solenoid relay to close and power from the battery cable to connect through to the starter. If that voltage is present then the solenoid or the wiring between the solenoid and battery or solenoid and starter is suspect. If that voltage is missing then the starter switch or solenoid feed line may have failed.