OT? armature question (rotary inverter)

My bet is that it was used to balance. I would think that if someone repaired the winding (which does happen) that person would have minimized the size of the blob.

I am apprized to see a commutator in a RPC though.

Wes

My bet is that it was used to balance. I would think that if someone repaired the winding (which does happen) that person would have minimized the size of the blob.

I am apprized to see a commutator in a RPC though.

Wes

Sorry - the double post gremlin stepped in.

What Wes, said, the blobs are probably for balance. My WAG is the rotor is out of a wound rotor induction motor. If this be the case, you didn't get all of it from the ebay seller. There should be some resistors and a short circuiting switch connected to the brushes that ride on the commutator-looking thingies. IMO, you would do well to abandon the idea of making a RPC out of this.

Bob Swinney

not making a RPC, maybe i used the wrong word, it's a 1600 watt "Redi-Line" inverter, i got the rest of it.

b.w.

RediLine makes motor-generators (more accurately 'motor-alternators') for converting automotive DC (12 - 24 volt) to AC for powering tools, etc. - so what you have is a DC motor coupled to an AC alternator in one package.

These used to be very popular with mobile locksmiths and similar trades for powering 120 VAC machinery in a vehicle.

'Inverter' is generally construed to mean 'electronic DC-AC converter' using solid state widgets.

These motor-generators (IMHO) are superior to inverters for motor loads

- they tolerate a lot more starting overcurrent without releasing the smoke.

Carla

William Wix> not making a RPC, maybe i used the wrong word, it's a 1600 watt "Redi-Line"

thanks Carla, i was specifically wondering about the blobs of JB weld on the armature in the photos.

Don't know what those blobs are. All the armatures I've seen balanced were done by drilling in an automatic jig. I'd think it would be tough to balance just by sticking some random-sized epoxy blobs on there, and I don't see any signs of filing. It doesn't look like the windings are soldered into the commutator, just punched. This CAN cause problems under load later on. Another thing I don't see is any form of winding restraints at the ends. Usually there's some form of ties(ribbon, straps, string!) to keep the windings in place so they don't come loose at speed. This seems to have been abandoned on cheap imported stuff, one reason the older motors are still out there kicking while the newer stuff ends up in the scrap bin. The commutators really don't look bad on your example, can't really see the slip rings well enough to comment. Hope the output is worth it, you can get 2 KW solid-state inverters now for well under $200.

Stan

Those blobs on the ends looked like someone might have tried to repair a broken or shorted winding.

As Carla said, those old rotary AC inverters you could run almost anything on. I had a 12 to 115 volt one that was supposed to be a 1000 watts. It would easily start and run a 1 hp motor. It was mounted on our service truck. The big problem was the truck altenator didnt put out enough to keep up with it unless the motor was reving up.

John

My opinion is that the blobs are to reinforce repaired windings. It would seem pretty unusual to balance this way since you would have to let the epoxy harden and then retry the balance. Balancing of armatures is normally done by shallow drilling the rotor.

Actually, I think its pretty academic. A good motor shop can test the armature and if it is good, then use it. I am curious what kind of circuit board would have been removed, the wires crimped, and the unit still operate. If you can obtain the circuit diagram a handy electronics guy should be able to build a replacement.

Don Young

thanks Stan. i really had a hard time deciding whether or not to get this mechanical inverter or the solid-state ones. i thought it would be nice to have a "true sine wave" inverter (supposedly this redi-line inverter is) but teh solid-state ones are very expensive. i was thinking if i could pick up a (used) true sine wave inverter cheap on eBay i'd be ahead.

b.w.

thanks Don, i'm wanting to take the armature to an electric motor shop, i just want to be able to walk in the door with some info of my own. the circuit board, yeah, me too, i don't really know if this thing ran well or at all. bought it from eBay, auction info said "as is" and "works good". in a previous post i said one of the carbon brushes was completely out/gone and the steel spring was rubbing against the slip ring, so, i suppose it COULD'VE worked but i'm doubting if it worked good. i don't really know if it worked at all without the circuit board and with the wires crimped, i didn't try it when i got it, i thought i ought to open it up first and check it out before i tried to run it. that would be the coolest, if i could somehow home-build a replacement circuit board (instead of coughing up the $230 or $400 they're asking for replacement parts).

thanks again.

b.w.

thanks John. (the specs say "continuous output watts 1600, surge output watts 2400". the continuous and surge amps are 14.5 and 22) (i thought i read somewhere you can run computers and such off this inverter, "true sine wave")

b.w.

I'm really wondering why you are messing with this relic from the early 1960's, at best. I'm pretty sure the field is 2-pole, so that means the thing has to run at 3600 RPM to make 60 Hz power. It is going to sound like a shop-vac when running.

There has to be a regulator to keep the dynamotor at 3600 RPM, and they can't use the field to do that, as that is what regulates the AC output. I can't figure from the armature photo how the speed regulator functions. They might have an AC frequency detector that cuts a series resistor in and out of the armature circuit, or even just switch the armature current on and off to regulate speed. Almost certainly it varies field strength to regulate AC voltage. Probably with all the regulation jumpered out it will run a bit above 60 Hz and 120 VAC output, which might be fine for running a small power tool at a remote site.

Jon

No big deal ! All the small cheap generators out there have gas engines running at 3600 RPM.

"Jon Elson" wrote in message news:KOidnbaQedS7JjvbnZ2dnUVZ snipped-for-privacy@giganews.com...

hey jon, i didn't know it was a relic. (i always figure like, a bow and arrow or a cannon can still kill someone just as well as a (what's a new high tech weapon?)) yeah it'll be loud, but i thought it would be neat if i could get a 1600 watt inverter that produced a sine wave for $185. the sine wave solid state inverters cost a lot more than that, and i figured it was mechanical so if there WAS something wrong with it i could fix it, i'd be leery of buying a solid state device used off eBay. (but i think i did end up getting screwed on this deal anyhow though, but wouldn't have known that going into it.) huh, thanks for the info about regulating it's speed. i assume that must be what the MISSING circuit board must've done. :-( the guy's auction said "as is" but also said "works good", which sucks. yeah, small power tool at a remote site. that was kinda what i was hoping to get out of it, and maybe also, i hoped, running the blower/burner on the boiler in my basement during a power outage in the winter. hoping that maybe i could charge up a "bank" (two deep cycle car batteries) and shut off the (noisy) generator and run the boiler (etc.) off the inverter for a while. it seemed from what i read this inverter was versatile, can run electric motors but also computers, etc.. noisier than a solid state inverter, but the trade off was that it didn't cost thousands of dollars. well, not yet at least.

b.w.