Q:i wont to make my slide door to open and close with out use my hand and i wont the electronic map to make itthank for all

The answer is you can't unless the motor is designed to operate in both directions. This is due to the location and connection of the starting coil of the motor. TexMav

Q:how to reduce single phase AC motor speed?

One way - the crudest - is to install a Resistance in between the origin and the end (series). Other more intelligent ways include transforming the cycle of the AC (120 Volts, 60 cycles) via Capacitors (this will chage the relationship between the Current (I in Amperes) and E (Voltage, in volts). For instance: if they use a big Capacitor in series with the feed of the motor, the Current will increment instantaneously, making the E (voltage to drop considerable). This will change the relationship (the more Amperes) the Less voltage. This will be fed to a circuit that will trigger (let go the charge of the Capacitor, discharging it rapidly and stopping the process in the way), generating a blow, a hit to the motor, that will last a mere fraction of the time interval, but creating enough torque for the motor to continue strong. Then the next pulse, and so forth, hundreds of times a minute. second or whatever. They were originally (they modified them again and again, many times, creating new things all the time!) called pulse motors, then, micro motors, etc Some may suggest to add more poles, but that would debilitate the motor output: more poles, less torque. You need more current, less voltage. This is called the Cosine Phi in this relation. When you change it, you generate torque (strength). All IS a relationship. The latest is brushless AC motors used in the industry to move heavy elements very rapidly and accurately.

Q:Its called a pancake motor. it generates 500 hp at 6500rpm for 60 seconds. and 420ftlbs of torque. oh also i like to mention its only 8in. by 12.5in. and 147lbs in wieght. wow. i hope to make a race car run from this powerful motor. and when i can figure out how to generate 2000kw in a car then i could synchronize 3 of theses motors and drag race this car. cool huh.

Watch back to the future

Q:when i did some research on ebay to buy motors, AC motors were usually rated for 120 volts, or 240 volts, while most DC motors were only rated for like, 24 or 50 volts. Why? Is AC better?

You need some sort of power source to power the motor. The most common AC voltages (in households at least) are 120V and 240V, so it makes sense that many AC motors will be designed to run off of those voltages. Most DC sources are batteries, so not surprisingly, DC motors will be designed to run off of typical battery voltages (i.e. 9V, 12V, 24V, 48V).

Q:I took apart a couple of small motors and found that they all have the copper coils attach to the shaft and spin around stationary magnets, rather then the other way around.The reason I'm asking is because they also have those two copper prongs touching the shaft in order to transfer the electricity back and forth, which wouldn't be necessary if you had the magnets spin and the coils stationary.

Will a spinning Neodymium Magnet induce a current in the copper coil which surrounds it? Yes, if the coil is oriented in such a way that it cuts the magnetic field lines. I am doing an experiment where i have a magnet inside of a copper coil which is connected to a voltage meter, and I am wondering if when the magnet is spun on its axis if it will induce a current in the coil. Does the axis on which it spins affect this or not? Yes, the axis is crucial. It is not really practical to set up a spin such that there is no current induced, but the orientation is important to get optimum results. Imagine that the Earth is a perfect magnet with north and south poles and perfectly aligned field lines, rotating as the Earth actually does. A coil of wire going around the equator would likely not have current induced, due to the fact that the coil would not be effectively cutting field lines. Making the earth rotate such that the poles went end over end would be an optimal orientation. Does the coil have to be bare wire or can it be insulated? It does not matter, but it helps to have lacquered wire and many loops of wire (instead of just one loop). The gauge of the wire does not really affect the result, but thinner wire is easier to loop multiple times in a small volume of space. I suppose that if you are generating high enough currents, the resistance in thinner wire and the heat generated may become a problem (generator windings usually breakdown because of overheating). Good luck!

Q:How to identify these motors ,also what they sound like to reconise the differences and finally what are they most suitable for?

All motors should have a nameplate that identifies the voltage, current, frequency, DC/AC and number of phases, which answers your question. They all sound the same. DC motors are used for low power applications, and for cases where precise position is needed, such as a motor for a CD player. Large DC motors are used in electric vehicles as they are operated from batteries. Single phase AC motors are used for appliances for the home, such as washing machines, etc. and for small industrial uses. Three phase AC motors are used for large industrial uses such as elevators, industrial equipment. Edit: Electrical locomotives and subway cars used large DC motors originally, but now newer ones use AC motors and use electronics to convert the DC from the lines into AC.

Q:What is the purpose of the encoder and how can you tell if it is working properly. thanks

Picture encoder as reporting device. (Watch dog) It can be use to report things like number of revolutions, position of the armature, speed, acceleration etc. this information can be used in may different ways, very often it is used as so called feedback control. It works like this; you give a command to the motor to go specific number of revolutions, encoder is watching what motor dose and confirms to the control device if it actually happens. Search Google or yahoo on steeper motors or servo motors to learn more.

Q:I sucked at physics in undergrad and I suck at physics even more now. Thanks.

probably 3 hp

Q:Braking principle of 220V alternating current motor

AC motor and its controlAC motor is divided into two categories: asynchronous motor and synchronous motor. According to the number of stator phases, asynchronous motors are divided into single induction motors, two-phase asynchronous motors and three-phase asynchronous motors. The three-phase asynchronous motor is widely used in industry and agriculture production because of its advantages of simple structure, reliable operation and low cost.

Q:will it affect the defroster or heater if i cut the ac belt?

I would suspect that the belt that controls the AC compressor is also controlling the power steering pump and possibly alternator. You would need to make sure the compressor has an indiviual drive belt. It would be easier to remove the fuse for the A/C system which should allow you to still have the use of the heater, etc.