Cu vs Al alternator windings

[wml52]

I'm in the process of purchasing a small, 7500 watt portable generator as emergency backup for my home just to run essentials, well pump, furnace, a few lights etc. In looking at various manufacturers I've noticed that more and more manufacturers are using aluminum wire for the windings in the alternator rather then copper. I suspect that this is being done as a cost cutting measure as well as weight. My question... are there any disadvantages in using aluminum wire in the windings vs copper?

Your thought would be appreciated.

Thanks to all.

[rustkolector]

I can't help you with the technical pro's and con's of aluminum vs copper alternator windings, but I recently picked up a new Champion 7kw 71530 dual fuel generator and it has copper windings.

Jeff

[wml52]

Hi Jeff,

I too looked at the Champion 71530 from Costco. I hate to break the news to you but if you look at the owners manual at the parts description for the rotor and stator items 50 and 53 you will see the letters (Al) which means it uses aluminum wiring for both the stator and rotor. Champion will confirm this as well if you give them a call.

[Frank S]

Just a personal opinion
Maybe just me but IMO aluminum makes great beer cans for bad beer.
 the Only aluminum wound generators I have had any dealings with were welder/ generators. A company I was with bought 50 of them for their light duty install work. the only advantage I could see in them was they were CHEAP price & lighter to toss in the back of a pickup. The disadvantages I saw in them was they kept my my service tech so busy trying to keep them running he didn't have time to do regular maintenance on anything else. Nit one of them lasted 6 months.
 Back in the 70s I mistakenly bought a SA200 Lincoln welder that had copper clad aluminum winding to replace my 20 year old Hobart also a 200 amp machine. I had used Lincolns that were copper so I figured the new one would be good Had I known about aluminum winding at the time I might not Make that I would not have bought it. Don't know what was different about the clad winding but the machine just did not perform nearly as well as my 20 year old Hobart.
 I will not or cannot say it was the machine's fault that it did not seem to have the push other machines dit.
 I will say though that to this day I have not ever knowingly bought another generator or welder that had Aluminum in it for my personal use.   

[Flux]

I would keep clear of aluminium, it has problems, the only virtue is cheapness. A few years ago it would not have been attempted, things were expensive and had to last. In the present throw away society things are so cheap that they can't be expected to last so people take chances. You can't find who made it in China and it would cost more than any warranty is worth to send it back so they risk anything that keeps the cost down.

It has higher resistance, suffers badly from vibration fatigue and is virtually impossible to connect satisfactorily in small sizes. It's not so bad for thick strip windings but in view of Frank's comments it may still not be totally satisfactory.

Flux

[dnix71]

Like Flux said, the disadvantages of aluminum are exactly the issues you will have with portable outdoor equipment. Humidity, heat and brittleness.

I can remember when the US was in at war with President Allende of Chile. We got most of our copper from there then. Pennies were switched from copper to cooper clad and house wiring made of aluminum was permitted even though it was known it would cause trouble. Even aluminum buss bars don't play well with copper wire because of the different expansion rates. Aluminum gets a hard thin non-conductive oxide coating almost immediately in warm moist air. It's just plain unsafe for a lot of applications, the only advantage is cost.

[rustkolector]

wml52,
I stand corrected. I guess it is copper plated aluminum I was looking at. I might have shopped around a little more if I had known about the AL windings, however, it appears I would have ended up with the AL windings in any event. I was looking for other features. It appears most manufacturers have been using AL for the last two years except for the inverter type generators. In reality, for a standby generator that will likely get low total hours on it, it probably doesn't matter if it is CU or AL. I think what matters most over the life of a good generator is parts availability and product support. Buy a trusted name.

That said, the windings on my 71530 look to be well varnished, >5% THD, and overall it looks very well made. I primarily chose the 71530 for its very neat and foolproof dual fuel system. My neighbors always have trouble finding gasoline during extended outages. If your need for a generator is absolute necessity, and not just convenience, then you may feel better owning two, like I do. Even an Onan, or a CAT will fail occasionally.
 
Jeff

[Mary B]

Northern Tool Northstar generator are a bargain. Honda engines, copper would brushless generator heads. My little 2700 watt has saved me a couple of times before I put in some solar.