How does a tachometer work?
A magnet that magnetizes "teeth" of an iron gear located on the motor. In general... The magnet magnetizes the "teeth" as the approach then de-magnetizes as they move away.. which creates an electric field.. The wire attached to the magnet connects to the tachometer which displays the rpm,
There are multiple types out there. The modern, most exact, is to have a laser or infra red light with a receiver on the opposite side. When the wheel ( or shaft rotates) it has a mirror or a tab that obstructs the path of the light every time it revovles ... then there is simply a chip to count the number of obstructions per minute. This one is extremely accurate and can handle some of the highest speeds.
But there are a host of older versions ... many still in use.
One is quite the same as above except there is a magnet on the shaft and a sensor ( Google 'reed switch' for example ) nearby that detects the magnet passing.
Another way is a chip attached to a switch that is physically pushed or contacted by a cog on the shaft.
Still another is to have a generator attached to the shaft and the Tach is actually a voltage meter telling the reading off that generator.
Finalley ... saved this one for last ... chances are you looked up this question because you wanted to know how the oldest Tachs worked back when electrical gear wasn't commonly used in cars and such. How did they pull it off back then? Well here goes: The end of the shaft had 2+ arms attached to the side that are weighted and would swing outward further and further, the faster the shaft rotated. The weights had a collar attached below them that would rise upward, the faster the shaft ran. Still with me? Check out this graphic if you need http:/www.railway-technical.comgovernor.gif the wieghts are the round black objects and the rising collar is green. So now all that is left is to have a hook ( with wheel to reduce friction ) that is hooked in the path of the collar so that it will get pulled up with the collar. The hook is attached to a cable ... on the other end of that cable is ( drum roll ) the sneedle of the Tach ... tugging it against a spring, over more and more as the shaft spins faster and faster. No electricity and no chips involved! Obviously this is somthing of a percision device and only as accurate as its most recent callibration ... but it worked enough. There were even hand held versions, very precise instruments that machinist would press against the axels of gears and shafts to get RPM readings. Now they have little hand held laser devices that are pocket size and much more accurate.
If you had a speedometer with a tachometer and you replaced it with a speedometer without a tachometer will it work?
My tachometer only works about once per year. How do you check for loose connections on the tachometer in a 99 Honda Civic Si?
My speedometer and tachometer in my 97 Jetta GT stopped working I replaced the Speedo sensor in the transaxle and it still doesn't work. What can I do?
The tachometer does not work on your 1998 transport and the motor was just rebuilt what could cause this?
it is a device that converts mechanical into electric measurements. it measures velocity. there are many types: electrical, mechanical, thermo-electrical... for example the mechanical tachometer converts the rotation motion into translation motion with the help of an axis so you can read it on the scale of the tachometer. sorry for not being so good at explaining this. hope somebody will be more documented.
A tachometer works by measuring how many time a spark plug fires. If the tachometer is designed to determine the rpm of an 8 cylinder engine it will not show the correct speed of a 2 cylinder engine. If I remember correctly if the tachometer designed for an 8 cylinder is used on a 4 cylinder engine it will show twice the number of actual rpm. So an 8 cylinder tachometer used on a 2…
THERE ARE TWO TYPES OF TACHOMETER. 1.D.C. TACHOMETER 2.A.C. TACHOMETER ALSO DIGITAL TACHOMETERS CAN BE CONSTRUCTED using various principles..... D.C. TACHOMETER its construction is very similar to a D.c. generator. it works on the principle of generation of emf wen a rotating conductor cuts the magnetic flux......when magnetic flux is constant then the emf produce is directly proportional to the speed of the armature that is coupled to the shaft of motor. A.C. tachometer its…
What is wrong with a Chrysler Sebring jxi convertible v6 if the odometer and tachometer only work periodically the lights on the clockradio also dim and the driver's side window has no power?
For the odometer/tachometer question the answer is in a solder that has come apart. I had the same problem. You have to take the instrument panel out to get at the control board in behind. There are two large blue resistors that surround a soldered connection. I had to solder this on both sides of the board. On the third try I had to disconnect one of the blue resistors to get at the connection…
In order to install a tachometer on your 1987 Monte Carlo SS, you must first find the tachometer wire by using an automotive diagnostic tool. Mount the tachometer on the dashboard. Connect green, red, black, and white wires to the distributor, ignition power, cigarette lighter, and headlights, respectively. Turn on the engine to test if the tachometer works.