1-long jumper 360-deg or 300deg... 2-ôskip groupö? 2

[electricpete]

http://www.uiitraining.com/b51a/100/15104ac_motor_rewind_intro4.htm

SHORT JUMPER: This method is defined as when PPGs are connected finish-to-finish and start-to-start. It is the most common connection method and is used extensively in single-speed motors and in all instances of unequal coil grouping. Connections of each phase are identical. This method interconnects adjacent groups of alternate polarity within each phase. Each jumper spans 180 electrical degrees.

Refer to the figure at right during the following discussion.
Typical short jumper connections for a four-pole motor winding would be as follows:

Begin at the start of A1 (As), go finish-to-finish, start-to-start, finish-to-finish, start-to-start, etc., to A10 (Af). C phase and B phase follow the same way. The connection sequence will be the same, regardless of the number of poles.

LONG JUMPER: This method is used when connections are made finish-to-start and start-to-finish. It is used mainly for connecting consequent pole, single-winding, dual-speed motors. In some cases, it is also used for connecting one or both of the individual windings in two-speed, two-winding motors. Connections for each phase will be identical. This method interconnects alternate PPGs of the same polarity within each phase. Each jumper spans 360 electrical degrees. Alternate polarities are achieved by using a single short jumper as the center connection of each phase.

Typical Short Jumper and Skip Group Connections


Refer to the figure at right during the following discussion.

Typical long jumper connections for a four-pole motor winding would be as follows:

Begin at A1 start (As), finish-to-start, finish-to-finish (short jumper), start-to-finish, to A10 (Af). Connection sequence will be the same regardless of number of poles.

SKIP GROUP: This term refers to the method of starting connections for individual phases. It can be used with either long or short jumper methods. It provides physical displacement between starts of phases to help eliminate potential short circuits

Using my terminology of sequence of groups A B’ C A’ B C’...

I think I understand the difference between 1-4 connection using short jumpers and 1-7 connection using long jumpers (plus one short jumper at the midpoint). It makes sense that the short jumper spans an arc corresponding to 180 electrical degrees (for example left side of A to left side of A’ with groups B’ C groups between). But they say long jumper spans 360 degrees... whereas I think it should be only 300 degrees (for example right side of A to left side of A with B’ C A’ B groups between.

Question 1: Do you agree that “long jumper” spans an arc corresponding to 300 electrical degrees instead of 360 degrees?

Another term they use is “skip group”, which they describe as connecting T leads 120 degrees apart (for example T1-A, T2-C, T3-B within A B’ C A’ B C’) instead of 60 degrees apart (for example (for example T1-A, T5-B’, T3-C within A B’ C A’ B C’) in an integral slot winding. But I thought skip group was also just another way to describe 1-7 interconnection of poles using long jumpers.
Question 2: “Skip group” also refers to any connection that involves 1-7 interconnection of poles, doesn’t it?


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(2B)+(2B)' ?

 

[zlatkodo]

Is there anything new in the new EASA article about skip pole, adjacent pole, short and long jumper etc?

Has anyone seen this publication?
Zlatkodo

 

[electricpete]

I saw this one "The potential pitfalls of parallel circuits" very recently issued:

http://www.easa.com/node/23584

But as I recall it didn't address much of what we discussed in this thread.

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(2B)+(2B)' ?

 

[zlatkodo]

Hi, Electricpete,
I thought this:

http://www.easa.com/techarticles/SkipPole_or_AdjacentPole

Zlatkodo