Yaskawa Servo motor

[ksouers]

A friend dropped by the house today after work. He brought a gift.



He said this had been sitting around the shop for about 10 years just taking up space. He first told me about it back in February or March but didn't have any details on it so I said “Yeah, I'll take it”. Figured they were just going to trash it and I can throw it away if it's not usable.

Here's the specs on it:
Model#: SGMG-09A2ABC
850w
5.39Nm
7.1 A
1500 RPM

It's not great, but it certainly doesn't look bad to me. The brake is locked up, so I have to get that removed. If anybody knows anything about this motor or has an opinion, please speak up.

I've been re-reading bvan's thread about his Fanuc motor to get some insight into removing the brake.
http://www.anotherpower.com/board/index.php/topic,214.0.html

Kevin

[Dale S]

I'm not an expert on these motors but the 7.1 amps and 1500 rpms don't look good to to me.

[birdhouse]

kevin-
i'm not familiar with yaskawa's, but i'd be willing to bet the brake is in the chamber between the two plugs.  hopefully you don't have to un-seat a bearing to get to it, but many times that is the case. 

just off the top of my head guessing (and you'll know more once you bench it) i bet a 5-6' blade set would give you 300w in 20mph winds???  again, super guess.  not a bad motor though!  especially for free! 

adam

[wilfor03]

Hey kevin

That looks like a really good motor you've got there. What's the voltage on that thing? Might be able to get 15vdc (once rectified) @ around 100rpm in

 a decent wind. Brake shouldn't be  a big deal to get off there. Some even use them for braking up on the tower. Been watching flea-bay for these types

of motors, and one just pops up on your doorstep  ....LOL.....Have fun with it, bro...

Bill

[dang]

http://www.yaskawa.com/site/dmservo.nsf/%28DocID%29/TKUR-69MTMD/$File/SGMGServoSpecs.pdf



Power input at 200 Volts.  Nice find.

http://www.yaskawa.com/site/Support.nsf/DMSD_Results?OpenForm&DMSDd=DMServo.nsf&DMSDq=Servo%20Products-SGMG

[ksouers]

Thanks guys.

Dale: No, the numbers aren't great, but I do think it will be workable. It would be nice if the amps or the watts were a little higher, but hey, I can't complain. The price was perfect. All the servo motors I've seen have been 1500 RPM or higher. I don't think any are rated any slower. Bvan seemed to indicate in his thread that the amp rating might be per phase, not overall. So the overall output could be higher. Don't know. I'll find out when I start playing with it.

Adam: You are right. The brake is in the middle chamber. I think I'll see how much power it takes to release the brake before removing it. I've almost got the encoder off, just one screw holding up the works (naturally ). The wind here hides out in Canada during the summer, it's non-existent except during storms. But come fall and winter it can howl like a Banshee. I probably won't get any real-world numbers out of it until about late September or maybe October.

Bill: Just using the numbers off the data plate it's 120 volts. I haven't seen any indication of what the volts are yet, but looking at some pictures of other motors it may be printed somewhere inside. We'll see. I'm not going to get my hopes up too high about the output. I'm sure it'll be much better than the little dinky things with which I've been experimenting.

Dan: Thanks for the links. Especially decoding the model number. That gives quite a bit more usable info than the data plate.

Free is good

Kevin

[ksouers]

Wow! That was easy!

Got the encoder and brake removed. All done in about an hour. It was much easier than I thought it would be.
Splitting the case was hardest, but only because it was the most time consuming. It really wasn't difficult.

I couldn't get the brake coil out, I guess it was a real tight fit. There are 3 bolts in the cover to hold it in place, I expected it to just drop out but it didn't. So, I removed the friction plate and actuator plate but left the coil in place. I can put everything back at a later date if I decide I need it.

If you want to see the innards bvan posted some pictures of a Yaskawa that he took apart. Mine looks identical.
http://www.anotherpower.com/board/index.php/topic,214.msg2666.html#msg2666

The rotor turns freely by hand, but it's not really easy. There is some friction from the bearings and of course the mass of the rotor. Hard to explain. There's no flywheel effect so it stops pretty quickly, but it's not hard to turn and there's no cogging except when the outputs are shorted. Then it's almost impossible to turn.

I quickly got out some clip leads, a small rectifier and VOM. I had to play Got 6 volts just twisting it by hand and 0.8 amps. Yeah, I'm gonna like this But it's going to take some fairly hefty blades to turn it.

I'll have a bigger rectifier assembled tonight and start some testing with a drill. This is gonna be fun!

Kevin

[Rover]

Cool!

" Yeah, I'm gonna like this  But it's going to take some fairly hefty blades to turn it."  Withough knowing exactly how har it is to turn, I'd still say good find.

My first step would be to get the unit into position so that you can test with some aux driver .. drill, whatever.. into bats.

I also think adding some mass to the hub may help you somewhat. Never know until you actually attach a blade hub, 3 or 4 lbs of blades (total) makes a big difference,.  Really hard to tell how it will spin when just hand turning. I have a 2HP Baldor DC motor that spins nicely with a small 5' dia blade set, yet by hand is not the easiest to spin (and that has brush drag).

Fun project !

Rover

[tomw]

Kevin;

It is hard to put a value on FUN! The learning and generated electron flow are side effects.

Many of us started with machines from the scrap bin that were not "ideal" they are just steps on the path.

Most importantly have some fun with it.

Tom

[ksouers]

Thanks Tom and Rover.

Got some testing in. I didn't assemble the bigger rectifier like I thought I would, so I just used my little one with 1 amp diodes. Didn't burn anything up I hooked up a little battery powered drill and gave it a spin. The little drill would spin it to 475 RPM with all the guts it had, that was putting out 32.5 volts. Much better than I expected though a little high on the revs. Slowing down to ~200 RPM got 13.5 volts. Tried measuring amperage but the drill would cut out as soon as it reached 3 amps. Tried sneaking up on it but still cut out at 3. Also tried spinning it both directions, counter-clockwise proved to have slightly more power by about 2 volts. Could just be the RPMs, though. I didn't tach the clockwise rotation.

Now I need to build a new tower. There's no way my little test tower will handle this 20 pound monster. Because of where I would have to locate the tower I'm limited to about 25 feet, the fall zone has to stay on my property. Any place else and I run into trees or just get closer to the neighbors, thus reducing the height. I think 4 inch sched 40 PVC would work.  Feel free to blow this one out of the water. I'd rather do steel pipe but have no welding equipment. Can wire welders be rented?

Blades. Store-bought or scratch? I'd almost rather go store-bought for the convenience but I don't think I can get them small enough, except the crappy sheet aluminum ones from Windy Nation. Carving out of wood doesn't appeal to me, I'm not a wood worker. But if I have to I will.

Kevin

[tomw]

Kevin;

For testing purposes you do not need brawny diodes / rectifier. They are actually more likely to pop if you run the volts too high into them testing than from too much current.

Simple voltage testing will not push any current through them unless you load it at the same time.

Tom

[ksouers]

Did a little more playing this afternoon, hooked it up to the bank with an ammeter.
The bank had been topped off by the solar panels since about 2:00, it was floating at 13.3 volts.
Powered by the battery drill the Yaskawa was putting 0.5 amps in at about 225 RPM (according to the tach).  A whole 6 watts.

Definitely going to need some big wind and a fast set of blades to get some power out of it. Or maybe pull a Chris Olson and gear it up


Kevin

[ghurd]

Are you testing it in IRP/Jerry or Star/Wye?

You can get more voltage per RPM in Star/Wye, at the expense of greater resistance.

That drag sounds more like minor eddy currents somewhere. In the laminations, maybe in the brake, etc?
If you can, get all the extra crap out, like the coils in the brake.
G-

[ksouers]

Hi G,
It still wired how it came from the factory, star/wye. 3 of the 7 terminals on the connector. 2 are for the brake, I guess the other 2 are unused.
I didn't pull the coils so I don't know for certain how it's wired. The coils weren't visible from the open end of the case, but I could see it had hemispherical magnets.

The drag feels more like a minor misalignment or pressure on the bearings. Perhaps from the glue that held the rear bearing in. There aren't any "sticky spots" like you might expect from a damaged or worn bearing, just an overall drag on the shaft. I'm going to split the case again to have another look, maybe scrape off the bits of old glue. I'll take another whack at getting the brake coil out, too.

The drag changes depending on how tight the case bolts are torqued down. The tighter the bolts the more resistance to motion that makes me think it's some kind of misalignment. There is a barely discernible cogging when turning slowly by hand. Easy to miss unless you are looking for it. Spin it too quickly and you'll never notice it.

Kevin

[ksouers]

I split the case again, got the brake coil out this time. Yes, it was a tight friction fit. I left the bolts in slightly proud of the case and smacked them with a dead-blow. The coil surrendered and popped out.

I then cleaned up the glue from the bearing and cavity. It was actually kind of rubbery, not hard and crystaline like CA or Locktite. I was able to rub it off with a paper towel.

Yes, there was some improvement. Not great, but better. I think it's as good as it's going to get. Spinning the bearing while it was out of the case proved there is drag in the bearings. Both the front and rear bearing spin freely without any roughness. The best way I can describe it is like a rubber seal that is pressing against the shaft. Anyway, reseating the bearing did offer some improvement. I don't know how much removing the coil contributed, if any. It certainly shaved a couple pounds off the weight.


Kevin