Power Windows in Cars

General Motors introduced another application of the technology in the late 1940s and started using it to control the roof tops of private vehicles in addition to power windows. Ford followed suit and incorporated hydroelectric systems into their convertible cars. Cadillac introduced power windows in its limousines in the 1970s as drop-down windows between the driver and rear passenger compartment. By the late 1980s, almost all cars on the international market were equipped with power windows. However, the Indian auto industry was still far from introducing power windows. 

Features Of Power Windows:

Keeping aside the generic feature of the windows being rolled up and down with just the touch of a button, the power windows come with some unique features that make them more user-friendly and convenient. These features can be summed up as follows:

1. Automatic Down: This is a very common feature in almost all power windows. This feature allows the user to make the windows go all the way down by just tapping the button once. The system uses a circuit to monitor the amount of time that the switch was held down. If the switch is held down for less than a second, the window goes down all the way to hit the limit switch and stops there. In case the button is held down for a longer time, the circuit analyses the time and stops rolling the window down as soon as the button is released.
2. Automatic Up: This feature is not very common as it has certain complications. The automatic up works in the same way as the automatic down. But, the automatic up feature poses a risk. While the window goes up, if anything gets in the way of the window, like a child's hand or a pet dog or cat's paw, it is highly likely to injure them. As the window won't stop until it hits the limit switch, it engages a risk of an accident. The only way out of this problem is the introduction of another circuit into the system, that can monitor the speed at which the window rolls up. As the speed is slowed down due to an obstruction, the circuit reverses the power back to the motor and the window goes down.
3. Courtesy Power-On: As stated earlier, power windows work only when the ignition of the vehicle is on. But some cars have a courtesy power backup which is supplied to the window circuit even after the engine is turned off. In case you forget to roll up your windows, this feature saves you from the hassle of turning your ignition on again, just to pull the windows up.

Mechanism Of Power Windows:

Power windows are controlled by switches and wires and are powered by battery or electricity. Power windows do not function if the ignition of the car is not turned on. Unlike the traditional windows, power windows do not have manual handles. They do not work manually. The basic power windows generally have control of all the four windows and can be controlled by the driver.

This is how power windows work:

1. The door on the driver's side is powered by an optimized 20-amp circuit breaker.
2. The power from the circuit-breaker is transmitted to a contact point in the centre, where the wirings of all the four windows meet, through the window switch control panel.
3. Then the two ends of the power contact is connected to the battery or electric motor and the vehicle ground.
4. When a switch is pressed, one of the two ends gets disconnected from the vehicle ground and gets connected to the power point at the centre. This distributes the power to the rest of the windows.

However, power window systems used in modern cars are very advanced in terms of technology. These days most of the advanced and high-end cars are equipped with multiple powered components like power windows, power doors, and power ORVMs (Outside Rear View Mirrors). In such cases, car manufacturers find it extremely difficult to convene all the wires together in one. That is why all the wires are merged into one module, and thus all the controls are monitored. Since, all the wires are merged into a single module, the power gets transmitted directly to the central wire module and then to all the four windows, at just the press of a button by the driver.

Advantages Of Power Windows:

Power windows are offered in almost all the vehicles these days. In high-end cars, it is offered as a standard and even in mid-range cars, it is at least offered as an option. The power windows eliminates the hurdle of the traditional handles which needed a lot of effort and time to open or shut the windows. The advantages of power windows can be listed as follows:

1. It allows the driver to control the windows with just the touch of his fingers.
2. It allows people with hand injuries or other physical complications to easily operate the windows.
3. Drivers can easily control the windows even while driving.
4. The master power panel in the front also allows the driver to operate all the windows simultaneously, without leaving his seat. This feature is very helpful in case there are children in the back seat.

Disadvantages Of Power Windows:

Although power windows have a lot of advantages, it might also have some drawbacks at certain instances. As it is powered by battery or electricity, it is always associated with the risk of a failure or a breakdown. In case of a power window failure, one cannot open or shut the window which might cause a lot of problem. Power windows might stop working all of a sudden. Listed below are the most common reasons that might cause a failure or breakdown in power windows:

1. Many a times, the window regulator also known as the window track, might stop functioning. This causes a power window failure.
2. Power windows might also stop working because of a broken motor, a broken cable pulley, or a broken switch.
3. Worn off window regulators might also be a reason behind a dysfunctional power window.

With all the advantages that the power window system has to offer on one hand and the limited disadvantages on the other hand, it is quite evident why most automobile manufacturers offer power windows as a standard these days.

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