AC induction motor manufacturing 1

[jag27]

what is a good web site to find out more about AC induction motor manufacturing. particularly coil winding, taping spreading etc.

thanks

 

[dpc]

http://www.easa.com/

Might be a good starting point...

 

[jag27]

I could not find any info here

could you please redirect me to the exact page

thnx

 

[aolalde]

Hello jag27:

The information you need is not open to the public. Normally each motor manufacturer and repair shops make their own research and development of manufacturing process.
EASA is an association for Motor Repair Shops and provides some technical support to members.

 

[SteveKW]

How about starting here...

http://www.google.com/search?hl=en&q=motor+winding+machine

 

[jag27]

where does taping of coils come into picture during the whole production process.
what are the different taping methods for formed coils

 

[electricpete]

Strands are provided with strand insulation. They are grouped together to form a turn and sometimes insulated with dedicated turn insulation.

The turns are wrapped into an oval shape, then pulled into a diamond shape using a coil spreader.

Then the ground insulation tape is applied by taping machine or by hand or by combination. May be half-lapped or edge-lapped (I don't think butt-lapped ). Also armour tape. Then later sometimes slot sections are pressed in an autoclave. Lead wires stripped. Corona suppresion applied if somewhere above 6kv.

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[jag27]

thanks electripete

that was really helpful

Also when you say strands, are strands like magnet wire ( copper wire with insulation on it)

so 1 turn( winding turn) is actually multiple strands made into a turn or do individual strands count as turns

is there pictures available anywhere which shows how each of the steps is done

 

[electricpete]

Strands would be similar to magnet wire from the standpoint that it is an individual copper that comes from the manufacturer with some kind of insulation (usually film) on it. However the strands used for form-wound motors are rectangular in shape (with rounded corners) unlike the strands used in smaller random wound motors.

Several strands are used in parallel to form a turn. They act almost like a single conductor except they are more pliable than a single thick conductor and less eddy current than a single thick conductor due to strand insulation. Several turns in series form a coil.

I haven't seem many good pictures on-line but Steve's google may help.

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[jag27]

what would happen if the insulation between the individual strands was to short out. i.e how critical is it that the insulation is of good quality

 

[electricpete]

I think strand insulation is not viewed as critical for the machines I deal with 10,000hp and less. It may be a different story for huge Roebel bars on large generators.

If there were no strand insulation at all the whole machine would run hotter due to the effects of eddy currents. If there is a localized defect in strand insulation it may result in a slight increase in local temperature. That will not be a problem unless it damages the turn or ground insulation. Failure of ground insulation usually results in immediate trip. Likewise failure of turn insulation ususally results in extreme heating which then fails the ground insulation and trips the motor quickly. For some machines with no "dedicated" turn insulation, the strand insulation plays the role of turn insulation and in that case failure of strand insulation = failure of turn insulation would result in motor trip within a short period.

I believe NEMA MW-1 calls for both voltage withstand capability and surge withstand testing of magnet wire strand insulation.

Anyone else is welcome to step in with comments or correct me if I have misstated something.

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[aolalde]

The following site could give you an idea of coil manufacture,

http://www.cmicoil.com/vpicoil.html