[elengeniero]

Hello all and thank you in advance for viewing this post,

I'm an electrical engineering graduate student at Cal Poly in San Luis Obispo. I'm doing research using a 3-phase 15kVA Dry-Type transformer. The transformer came with a delta high and delta low connection. The high side winding is solid aluminum (round) conductor. The low side winding is solid aluminum (strip/bar) conductor. The winding connections were originally made by the manufacture by welding them to aluminum mechanical connection blocks. The supply and load wires were connected using a screwed compression fitting.

For my research I need to break the winding connections so that I can terminate them to wire and connect them as I please (delta/wye; wye/wye; etc.). I realize that depending on how I connect them the rated line current will change and I've calculated that. I ended up cutting the conductors as close to the weld as I could. I would like to terminate all of these conductors with a ring tounge lug so that I could create the desired winding connections using a terminal block mounted on the side of the transformer panel.

The problem I'm having is finding the right type of lug/connector to terminate the strip/bar shaped winding. The strip is about 1/16" thick by 3/16" wide. I'm sure I can find a lug to crimp onto the round conductor (about 10AWG) but all my google searches for the bar winding are coming up empty. Any suggestions? I'm thinking I may have to machine my own mechanical compression lug.

Any help would be appreciated.

Thank you,

Ariel

 

[EB Electric]

Pictures would help... Have you checked out Burndy,? they make a ton of connectors

 

[MWayne]

My first thought is to use a large enough mechanical lug to fit across the 3/16" wide bar and carefully tighten it.

http://lugsdirect.com/images/S6-slotted-500x.jpg

I forget how those things are speced. Size wise but one that fits a 3AWG conductor ought to clamp down over your bar without distorting it too much, then you tie in the temporary connections using the given hole.

 

[Big John]

If this is a temporary project transformer and will never be left unattended, just use a regular mechanical lug. It will be good enough for the low current you're dealing with.

In the field these connections are made by brazing on copper shunts; I don't know of a mechanical method designed to terminate a winding like that.

 

[someonespecial]

Maybe a lug like this with a square interior would work to clamp onto the strip. Bolt two together and you can terminate your wire the same way

 

[micromind]

A split-bolt would work pretty well.

I've actually done this where the factory weld has been broken loose.

Another possibility is to drill a hole in the end of the flat winding bar and bolt a lug onto it. Use a regular washer plus a Belleville; this will maintain clamping tension.

You'd need to be careful with any type of low pressure compression joint though, a transformer bus is quite a bit softer than a regular busbar and cold flow will be a problem. Hence the Belleville recommendation.

 

[Meadow]

Hello all and thank you in advance for viewing this post,

I'm an electrical engineering graduate student at Cal Poly in San Luis Obispo. I'm doing research using a 3-phase 15kVA Dry-Type transformer. The transformer came with a delta high and delta low connection. The high side winding is solid aluminum (round) conductor. The low side winding is solid aluminum (strip/bar) conductor. The winding connections were originally made by the manufacture by welding them to aluminum mechanical connection blocks. The supply and load wires were connected using a screwed compression fitting.

For my research I need to break the winding connections so that I can terminate them to wire and connect them as I please (delta/wye; wye/wye; etc.). I realize that depending on how I connect them the rated line current will change and I've calculated that. I ended up cutting the conductors as close to the weld as I could. I would like to terminate all of these conductors with a ring tounge lug so that I could create the desired winding connections using a terminal block mounted on the side of the transformer panel.

The problem I'm having is finding the right type of lug/connector to terminate the strip/bar shaped winding. The strip is about 1/16" thick by 3/16" wide. I'm sure I can find a lug to crimp onto the round conductor (about 10AWG) but all my google searches for the bar winding are coming up empty. Any suggestions? I'm thinking I may have to machine my own mechanical compression lug.

Any help would be appreciated.

Thank you,

Ariel

If you can unweld them. If you do cut them be prepared to sand paper the enamel off. I would recommend a crimp connection to each lead rated for AL wire (like when linemen crimp in coming wires at the service head). Another option would be a Burndy connector block which is a screw down terminal.

Of note, when taking the leads off the transformer make sure you mark each of the coil leads with the correct polarity. that will really help down the road.

What type of current will the leads be subjected too?