Author Topic: Help needed: no output on ST5  (Read 6484 times)

vtmetro

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Help needed: no output on ST5
« on: August 26, 2015, 07:24:01 PM »
re. ST5 with brushes and AVR

Hello all, it's been a long time since I've been on the forum or used my Listeroid Metro 6/1. I want to get it ready for winter and add the improvements I always wanted to do, so I checked it out in the shed where it is mounted.

A mouse had recently started a nest on top of the generator's brush terminals. I cleaned that out before trying to start and checked the brushes and terminals. They looked okay. I pulled the brushes and wiped them and the rings with a denatured alcohol moistened paper towel. The rings looked shiny and the ends of the brushes weren't cracked or broken. This is a low hours engine and genset. It doesn't look new only because there hs been some rust on the flimsy doghouse sheetmetal on top of the gen head where the thin paint cracked off. One of the things I want to do now is remove it and build a proper junction box off the generator.

Anyway, the Metro started easily, and the genset spun up and I had 120V showin on the meter with the panel switch still in the "off" position. I left the engine to warm up for aa minute to check the water lines and radiator to make sure the cooling system was working. When I got back I noticed there was no indication on the meter, and moving the switch to "on" no difference. There was no sign of electrical overheating anywhere, and there had been no electrical load on the generator since it was started.

I own a VOM, but am not quite sure where to start checking for the problem. The switch and the light are very cheesy quality, (one of the light socket contacts feels loose) and I'm wondering if that circuit is the source of the problem. The switch and light (incandescent) are in series together, and the leads that feed them go back throught the pass-through into the generator case. Thery're bundeld together with some other wires in an insulator sleeve, so I can't tell exactly where they go. Is that to the field?

So first question is, can I jumper the two leads together that go to the switch and light to bypass them?

And if that doesn't work, Is there a troubleshooting procedure of steps to test with the meter to find out where the problem is? A link is fine if there is somewhere in the forum. Or if not, can someone make suggestions?

I greatly appreciate it.!






vtmetro

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Re: Help needed: no output on ST5
« Reply #1 on: August 26, 2015, 09:29:06 PM »
After finding a tip elsewhere on the forum I labeled the leads to the bridge rectifier with masking tape and pulled that out. Checking with an ohmeter showed that it was shorted in one leg.

The label on the old one said 10 amps, It so happened that I had a 25 amp 600 PIV bridge rectifier on hand (GBPC2506) so decided to replace it with that one.

I was able to salvage the aluminum heat sink from the original rectifier by knocking out the plastic part. One good hit and it slid right out of the extrusion. It was only held in by a couple of thin lines of cement. There was NO obvious contact between the actual rectifier portion and the heat sink, I discovered, and no heat sink compound. There was an air gap between the metal and plastic. What a piece of junk!

But one cool bit of luck: the new rectifier slid into the extrusion perfectly. Since it had a hole in it already, I just drilled through the mounting hole in the heat sink and mounted it with a 10-24 x 1-1/2" bolt a nut and some Locktite. Oh, I used heat sink compound between the bridge and the sink this time.

The wire terminals seem just a little loose since they weren't exactly the same size, so I slightly crimped the tops, and then they made a firm connection with the spades.

Started the engine up and the meter swung up to indicate I had line voltage. Woohoo!

Here's the new rectifier:




Tom

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Re: Help needed: no output on ST5
« Reply #2 on: August 26, 2015, 10:16:55 PM »
Since you have an AVR in the doghouse, my suggestion would be to get a quality grey metal electrical box and mount it in the same location as the dog house. The light and switch have no functional purpose so they can be removed. Put the meter or a new better one on the wall near your AC connector.
Tom
2004 Ashwamegh 6/1 #217 - ST5 just over 3k hours.

vtmetro

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Re: Help needed: no output on ST5
« Reply #3 on: August 27, 2015, 01:14:02 AM »
Hi, Tom, I have a new quality metal enclosure that I bought for the purpose awhile back, also a transfer switch.

By same location, are you suggesting mounting it on top of the generator, like the present doghouse, or do you mean on the wall where the AC connection/meter transfer switch will be?

Would the reason for continuilg to mount the AVR on top of the generator be to keep the control leads as short as possible?

38ac

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Re: Help needed: no output on ST5
« Reply #4 on: August 27, 2015, 03:14:25 AM »
Both of my ST heads had rectifiers like that and both went poof in short order.  You can remote the junction box if you wish or if engine and head are bolted down and run smoothly you can bolt the new box to the head as I have done with good result.

As an aside good practice for long life means getting the units settled down, be it engine, head or XYZ. All will shed parts and pieces when shaking about  and at the worst time when asked to preform long term.

We are in the midst of moving and at the new place my generator shed is going to have lots of concrete under the engine and under both of the generator heads all of which will reside on their own plinths. 
Collector and horder of about anything diesel

vtmetro

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Re: Help needed: no output on ST5
« Reply #5 on: August 27, 2015, 02:06:24 PM »
Thanks 38AC, I think I would like to mount the AVR on the wall about 2 feet from the generator, then.

I do have a good mount setup for the listeroid and gen head, but am always open to improvements to any part of the setup, so comments are welcome.

The mounting I've used is first to pour in an excavation a pan shaped reinforced concrete slab with a 1 foot square section rim. At the bottom of the pan on the concrete slab I have a rubber horse stall mat. Set on that are two railroad ties. Bolted to the ties are the steel frame that the listeroid and generator are bolted to. The concrete pan was then filled with graded stone and sand up to the top of the railroad ties to provide damping.

I think I should really try to improve balance to the very best I can do now that the base seems reasonable. I have looked at a couple of the balance threads, including yours which is very helpful.

vtmetro

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Re: Help needed: no output on ST5
« Reply #6 on: August 27, 2015, 02:22:25 PM »
38ac re-reading your posts, when you say "on their own plinths", do you mean that the gen heads will be isolated from the engines to reduce vibration? This is something I've wondered about doing, myself.

The only difficulty I wondered about is whether the poly-vee belt would then vibrate too much not to skip a groove or have other problems. I guess it would depend on how much the engine vibrates, and from the sound of it you've really worked that down to a minimum.

With really solid concrete mounts, also that would also help. So I think I see the direction you're headed.

In my case, I could probably do the same by cutting the steel frame between the gen head and engine, and possibly removing the horse mat and gravel, and pouring the pan with concrete, embedding the railroad ties.

38ac

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Re: Help needed: no output on ST5
« Reply #7 on: August 28, 2015, 01:42:23 AM »
Yes they will be separated but my set up is going to be a MP Blackstone that is 5 times the HP and 6 times the weight of a Lister but still 1 cylinder and 7-750 RPM.  Its going to have two heads belted up, a 30KW 3 phase to operate my machine shop and a 15KW ST for household grid back up. The engine plinth block and one for each head will be poured first then the floor poured around them with expansion joint material separating them. Maybe extreme but the heads will be as isolated as I can make them.  With a well behaved 6/1 a person could very well do with one slab and bolt everything down but I wouldn't skimp on the concrete. For all the problems that shaking will cause and the irritation of ground thumping whats another yard of concrete in the long run? But that's just me  ;)
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dieselgman

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Re: Help needed: no output on ST5
« Reply #8 on: August 28, 2015, 01:54:41 AM »
You'll have to show us that Blackstone when you get around to messing with it!   :P

dieselgman
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vtmetro

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Re: Help needed: no output on ST5
« Reply #9 on: August 28, 2015, 03:00:51 PM »
Quote
For all the problems that shaking will cause and the irritation of ground thumping whats another yard of concrete in the long run? But that's just me 

Well, sounds reasonable to me!

That sounds like a great project, too. Look forward to seeing it going together if you take any pics.