Author Topic: Growling ST 3000 Watt generator head  (Read 12453 times)

BruceM

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Re: Growling ST 3000 Watt generator head
« Reply #15 on: January 13, 2006, 09:23:44 PM »
Thanks Doug!
I'm going to print out your note and go have another look.
Bruce

Doug

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Re: Growling ST 3000 Watt generator head
« Reply #16 on: January 14, 2006, 12:45:37 AM »
How about posting some pictures as you go and if things start to bad stop, post, and wait. I'll make an effort to look in on this discussion a couple of times a day when I'm on shift ( why do I spend more time on the computer at work where I don't officialy have internet access??? )

Doug

BruceM

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Bearings out, selection question
« Reply #17 on: January 14, 2006, 04:57:58 AM »
Doug- thanks for the instructions.  I was able to drive the shaft and bearing  out of the tight end bell using a wood drift and a hammer.  Sorry to bug you again but you obviously know your bearings!

The small bearing seems fine (I'll replace both), but the larger one at the pulley end does have a spot that doesn't feel right, though that could have been from using a gear puller to get it off the shaft. The big bearing was not at all tight in the housing; your comments on clearances and China QC came to mind.

The Larger bearing is 6307-2RS (Made in China, seal on one side only), and Grainger has a double sealed NTN equivalent.

Question:  The smaller bearing is 6305 ZX (Made in China no seals).  There are two NTN bearings the right size- one has LL type seals, the other ZZ type seals.  (Both double sealed.)  Which should I get?

Bruce


Doug

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Re: Growling ST 3000 Watt generator head
« Reply #18 on: January 15, 2006, 10:04:05 PM »
Sorry I thought I told you....
ZZ is the code for sheilded, dirt can still get in but the bearingis mostly covered and only open by a very small amount near the inner race. The nice thing about ZZ is you fill the cup inside the end bell with grease before you slid it all back together it will "pump" some gease into itself, but if that gears becomes fowled with dirt or water that could be a down side.
2RS is a fully sealed bearing, use it never grease, it and toss it when it gets noisy...

As far as the LL type in NTNs, I can't be sure what that means. I've nerver used a NTN there's nothing wrong with an NTN but I only use FAGs or SKF I know and completely trust them. I've changed what seems like thousands of motor bearing over the years and can only think of one case that FAG let me down, in the early 90s when somebody made a boo-boo at the factory and some were shipped with the grease in the 2RS lot.

Doug

BruceM

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Re: Growling ST 3000 Watt generator head
« Reply #19 on: January 15, 2006, 11:20:27 PM »
Thanks so much for help, Doug.  I think I'll go with the totally sealed bearing.  Here in AZ dust is the problem.  (Brown air today from high winds, in fact. We need rain/snow badly, 81 dry days so far.) 

Best Wishes,
Bruce
Snowflake, AZ

Doug

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Re: Growling ST 3000 Watt generator head
« Reply #20 on: January 16, 2006, 03:51:25 AM »
You know I've never seen an ST head, but a rotating machine is a rotating machine. Whats not clear in the technical information is that these motors are manufactured to a eroupean metric frame size( IEC type as aposssed to NEMA T we generaly see ) we don't commonly use in North America. The ST-3 appear to a short frame version of the ST-5, they saved money by using the same tooling to build both. A 6207 main bearing is massive over kill for this ap by a factor of about 2 to 1. Just to put that in persective for you a high quality motor like a Baldor rated at 5hp might only have a 6205 ( just off the top of my head ). This is good it means it can take a much higher radial load a verry good thing in a belt drive system like this where you might have to realy crank the presure on the belts to keep it from slipping.

Oh ya and don't do anything like use lock tight to hold bearings on shafts or in housings it doesn't work.
Don't take a center punch and pean little dents in the bearing housing or shaft to try and make it tighter. This does work but it shortens the bearing life because it distorts the outer/inner race and causes rapid wear. There are tables to match bearing diameter and bell housing fitts but I'll be dambed if i can find them, ask your bearing dealer for this information and mic the shaft and housing if your concerned. If you do have a problem any good automotive machine shop can bore out the housing and make a steel insert for under 100 bucks that will never let you down again and shafts can be rebuilt using a process called sub arc welding and remachined (this is more expensive).

Doug

hotater

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Re: Growling ST 3000 Watt generator head
« Reply #21 on: January 18, 2006, 03:48:51 PM »
RE:  RE-building shafts---

I've re-built one of the early Chinese 5-ST experiments a couple of times.  Both ends of the main shaft were undersized for the bearing and wore down even more so.  I didn't sub-arc weld  but did turn the shaft down and shrink on a sleeve which was then re-turned and ground for the proper fit.  That's a job most maintenence machine shops can do for you.
7200 hrs on 6-1/5Kw, FuKing Listeroid,
Currently running PS-Kit 6-1/5Kw...and some MPs and Chanfas and diesel snowplows and trucks and stuff.

BruceM

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Re: Growling ST 3000 Watt generator head
« Reply #22 on: January 18, 2006, 04:27:02 PM »
Thanks Hotater and Doug.  I've got the new bearings and will install on the next decent day.
The bearing fit on the non-pulley end is too tight, and I"ll check the fit with the new bearing to see if I need the shaft turned.  The big bearing to housing fit needs checking too- it was perhaps too loose.

The ST-5 head was not available when I had my Lister freighted.  I wish it was as the ST-3 only has one set of brushes, not two.  Because of my derated power at the 5600 foot running elevation, I think the ST-3 will be OK, and I'm still hoping to get a 240V 3KW PMG generator from George once that design is available. 

Bruce



solarguy

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Re: Growling ST 3000 Watt generator head
« Reply #23 on: February 18, 2006, 06:27:08 PM »
My ST5 head growled.  I took it apart and inspected/greased the factory bearings.  I didn't see/feel any problems so reinstalled the original bearings.

Later on, after some experience with the head, I also discovered that if one leg is loaded significantly more than the other, it makes the noise.  I also find it interesting that a given load plugged into one leg definitely makes more noise than the exact same load switched to the other leg.

Good luck and have fun!

troy