# "Motor-Wiring Lessons"



## HMF (Jul 2, 2011)

I found this on another forum and was wondering if it is a correct generalization of how a 110 Motor is wired.
I would like to learn, in simple, basic terms, how 220 motors are wired too, but when I get a book, it goes into SO MUCH DETAIL, I get lost!
Same thing with descriptions online- so complex!

"A 110 motor has 2 windings (three if it is 110/220). One is connected whenever the motor is running, and one goes through an internal switch, and is used for starting only. Each need 2 wires that connect to 110VAC.

The start winding is automatically switched out, and you should not need to do anything but hook it up, the motor takes care of switching it off.

If these wires are labeled 1 thru 4, with 1 and 2 being the "run" winding, and 3 and 4 being the "start" winding, then.....

if 1 and 3 are connected, and 2 and 4 are also, the motor will start and turn one direction, maybe clockwise, when power is hooked with (for instance) hot on the 1,2 group, and neutral on the 3,4 group.

if instead, 1 and 4, and 2 and 3 are connected, it will start the other direction.

The usual wiring sends power through one switch, and uses a second to reverse the start winding versus the run winding, as per above.

it can also be done with a single more complex switch (known as a "drum" switch)."


Thanks in advance!


Nelson


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## hermetic (Jul 9, 2011)

Hi Allthumbz,
 My advice is from the UK,but simple single phase motors should be the same universally. We usually mark our windings A1 and A2 for the run winding, and Z1 and Z2 for the start winding. To reverse the motor we swap the position of Z1 and Z2. This effectively reverses the polarity of the start winding and thus reverses the direction of the motor. A synchronous motor (that is one whose speed is governed by the frequency of the supply, we have 50 Hertz, you have 60 hertz) will actually run in either direction if you just use the run winding, it is the direction the start winding starts the motor turning that sets the direction of rotation. Hope this helps you!
Phil.


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## HMF (Jul 9, 2011)

If I understand correctly, this motor has 4 wires to hook up.

What about a 220 motor, especially a 3 phase motor?

Thanks,


Nelson


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## hermetic (Jul 9, 2011)

Hi Nelson, Our three phase is a little different to yours. We use 240v on each phase which gives us a nominal voltage of 415V between any two phases. There are three coils, A, B, and C. coil ends are marked A1&gt;A2  B1&gt;B2 and C1&gt;C2. For star connection, connect the three supply lines to A1, B1 and C1, and connect A2, B2 and C2 together. For delta, (sometimes also used for low voltage) connect A1 to B2, B1 to C2 and C1 to A2 and connect one supply lines to each of these junctions. If you look at this in diagram you will see that in star, there are two motor coils between each phase, whereas in delta there is only one coil between phases. In the USA I believe your 220V system uses 2"hot"wires which are effectively two phases. This makes your 220V system similar to the UK "split phase" system, which is pretty rare except in very remote areas such as farmsteads in Scotland etc. Our main systems are 240V single phase used mainly for domestic or light industrial/agricultural use, and the three phase 415V system used by industry and agriculture. I am lucky to have three phase 415V in my shop, which means I can buy ex industrial or school/college machinery and wire it up without phase converters and VF D's. Hope this helps, but remember my knowledge is based on UK training, and conditions elswhere may vary!
Phil


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## Starlight Tools (Jul 19, 2011)

Nelson

this discussion could open a massive "kettle of fish"

First and foremost there really is no "one" way a motor is wired up. Secondly there is really no such thing as it's just a motor. 

But the basics are that you must have a rotating portion, usually refered to as a rotor and a stationary portion usually refered to as the stator. By creating a series of collapsing magnetic fields between the rotor and stator, the rotor is pushed away from the like magnetic poles and pulled towards the unlike poles. This is acheived by using some method of phase shifting in a single phase motor. Three phase motors automaticaly have that phase shift built in which is why they are so much more effiecient. This phase shift can be a winding that has a different wire size and number of turns, or one ofr more capacitors or a mixture of all of them. As these fields chase themselves around the windings of the motor, the rotor continues to spin. 

Now there are motors that have only two wires coming out and they will run. Others have 3 or more wires. It all depends on how the motor is connected internally. four wires could be a reversible single voltage motor, or a non reversible dual voltage motor.

In North America, the motor windings of an induction motor are usually tagged as 1,2,3.4 and the start windings are generally 5 and 8. 

A good book on Electric motors is Fractional and Subfractional Horsepower Electrical Motors by Cyril G. Veinott and Joseph E. Martin

Walter


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## Tony Wells (Jul 19, 2011)

Walter covered it well. I recommend:

http://www.amazon.com/exec/obidos/ASIN/0962322962/wwwelectrical-20

for anyone working on their own shop.


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## HMF (Jul 20, 2011)

Thanks, guys, I will check those books out-

I really need something like "Motors 101" to spoon feed it to me slowly.

I purchased "Industrial Electricity and Motor Controls by Mark Miller (Author), Rex Miller 
Rex Miller (Author)" and it was way too advanced. 

http://www.amazon.com/Industrial-El...r_1_11?ie=UTF8&amp;qid=1311165784&amp;sr=8-11

There is also a book "Electric Motors and Drives: Fundamentals, Types and Applications (3rd Edition) by Austin Hughes" that looks pretty good:

http://www.amazon.com/Electric-Motors-Drives-Fundamentals-ebook/dp/B00146BMR4/ref=pd_rhf_p_t_1

I want to be able to wire up my machines' motors without blowing myself up!

Nelson


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## Starlight Tools (Aug 7, 2011)

Reported by Hogg on Today at 04:16:23 PM. They left the following message:

Thank-you from Hogg


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