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Generac Generators (SEARS, etc.)

Dyna generator?


I have a 4kW generator with 8hp Briggs&Stratton engine and an alternator by Dyna / Wynco...

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  #1  
Old 01-31-2011, 05:44 PM
Warren914 Warren914 is offline
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Default Dyna generator?

I have a 4kW generator with 8hp Briggs&Stratton engine and an alternator by Dyna / Wynco Incorporated.

When I brought it home the engine ran but it produced no AC output. A quick field flash with an electric drill brought it back to life, albeit temporarily. I let it run for about 30 minutes with a 500 watt lamp load. While listening from upstairs, the engine speed dropped considerably, and then went back to full speed. Checked the generator and the AC breaker had tripped. I reset the breaker and the engine speed dropped again, evidence of a very heavy AC load.

Next I pulled apart the AC panel and found some bad wiring on the idle control circuit. Its AC wiring was badly frayed, the circuit board was broken, etc. The whole thing was removed and the AC output rewired and reassembled.

It no longer produces AC. It seems to be a brushless output. Three lines feed from the generator to the electrical panel. I've tried flashing with the drill, quickly brushed the lines with a 12V battery, both with the engine on and off. Nothing. The capacitor inside tests perfect and the coils do not appear to be damaged. Each output coil seems to be approximately 0.7 ohms and the coil connecting to the capacitor is about 2 ohms.

This technique looks kind of scary but may be the last resort.
http://www.endtimesreport.com/dead_gen.html

Any suggestions how to bring this thing back to life?
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  #2  
Old 01-31-2011, 06:58 PM
pegasuspinto pegasuspinto is offline
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Default Re: Dyna generator?

That article contains nothing but hokus bullsnot. From beginning to end it's wrong, dangerous, scary. You can NOT flash with AC. terrible.....
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Old 01-31-2011, 07:00 PM
Jim Rankin Jim Rankin is offline
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Default Re: Dyna generator?

Do not do it!

Just not worth taking the chance and there's better, safer, easier, cheaper ways of doing what needs done.

What you're trying to do is to re-establish a magnetic field in the iron of the generator. Mostly in the rotor iron, but the stator iron will help too. When you use a method like a drill plugged into the output, you are working on the magnetic field in the stator/output iron. A more direct method is to flash the field. It takes DC current, from a battery usually is easiest. Doesn't have to be a large battery or high voltage, a couple of flashlight batteries in series (3 volts) will usually do it, but sometimes a 6 volt will be required and a 12 volt can be used. With the higher voltages, I like to have a lightbulb in the circuit to limit the current flow just a bit and make sure that there's actually a circuit through the field (the bulb lights when you flash the field).

However, first check the AC output of the set with a good meter with it running at governed rpm. If you have more than a few volts of AC output on the lines out of the generator, you probably don't need to flash it. It still has a good magnetic field and your problem lies elsewhere, most likely the regulator or exciter winding.

With a capacitor regulated set, you may not have a regulator anyway, but if you do, you may want to disconnect it before flashing the field. That will also give you a place to attach your leads to flash with. Connect positive battery to positive field wire/Negative to negative. You really just have to make a spark, putting current through the field with the engine stopped, but you can leave the battery connected and watch the AC output as you run the set at full speed and see what you get out of it. AC output should be proportional to the DC you put into it. If it needs 18 volts to make 120 and you apply 6 to the field with the generator turning at governed rpm, you should get about 40 volts AC out.

If you can get AC output while flashing, then stop the set and reconnect the regulator and try it. If nothing, that's pretty good evidence that the regulator or exciter is bad.
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Old 01-31-2011, 08:25 PM
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Talking Re: Dyna generator?

You know that there is a lot of just plain BS on the internet. Flashing a Genset Field Coil from the Stator Winding, just shows that the writer does NOT understand the technology, that he is messing with. You need to use a DC Current across the Field Coil. many folks us a 9 Vdc Battery and others use a 12 Vdc Battery, for this job.
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Old 01-31-2011, 10:13 PM
Lloyd H Lloyd H is offline
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Default Re: Dyna generator?

I was very disappointed in the article as well, however, the AC to the stator works, works well and is recommended by at least one generator maker, Pincor. It works by using the stator windings as a transformer to induce AC in the exciter winding, which is rectified by the diodes to DC which flashes the field. The procedure is outlined in the Pincor USERs manual, no doubt pre OSHA but none the less effective Pincor recommends two 100 Watt lamps instead of three. Certainly due diligence would be required, I feel there is a good chance it would work on a brushless set as well. Also once flashed and generating the lights indicate the difference in frequency of the two sources much like paralleling lamps ie. two dark and the units are synced. Just like the days before syncroscopes. Lloyd H

Last edited by Lloyd H; 01-31-2011 at 10:20 PM.
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Old 02-01-2011, 01:24 AM
pegasuspinto pegasuspinto is offline
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Default Re: Dyna generator?

In the end, of course all those methods CAN work, because so many sets just need a tickle of juice to get excited. A lot of them would self-excite if someone started them and just walked away for a couple of hours. But the bottom line, is the original poster already flashed his set just fine, it's probably got other issues.

I am not sure where that guy gets the idea a power staton needs something special to excite. I'm willing to bet almost all power plants can do a cold start to a dead grid at any time, off of their own standby power. And even the largest units could be flashed by a car battery....
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Old 02-01-2011, 08:35 AM
Warren914 Warren914 is offline
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Default Re: Dyna generator?

There are five wires coming from the stator. Two connect to the capacitor, and three are the AC output lines. There is continuity between the three AC wires, and no leakage to the chassis. There is no voltage regulator or external field wires. The rotor windings have been sealed in a sort of rubber coating and I can't see any diodes.

Likely pull the end off again shortly for a closer inspection. Although the capacitor tested good on a Sencore LC102, I may try another one in its place. I'll have to dig around some unused motors for an appropriate AC capacitor.
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Old 02-01-2011, 09:51 AM
K D Redd K D Redd is offline
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Default Re: Dyna generator?

This is a brushless unit is it not?. If so you need to check the rotating diodes on the rotor. Some will also have MOV's across the diodes.

Kent
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Old 02-02-2011, 12:05 PM
Warren914 Warren914 is offline
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Default Re: Dyna generator?

It's a brushless generator.

I need to pull the end off again and take a look. I didn't notice the diodes on the rotor when it was apart earlier and the windings have been sealed in a rubber type coating. Might have to get the heat gun out and do some digging.
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Old 02-02-2011, 07:39 PM
Daverepair Daverepair is offline
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Default Re: Dyna generator?

All the Winco's I worked on of that size either had a bad diode or bad capacitor/wiring to the capacitors. The diodes were soldered to the end of the rotor windings and bolted to a metal disc near the bearing. You have to unbolt the diode(s) to test it or them. This usually means removing the stator. Use a meter with a diode test position if you can.

If you go to Winco's website they have alot of good downloads for Winco/Dyna products

Download the "rotating field troubleshooting guide" this should help
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Old 02-04-2011, 04:24 PM
Warren914 Warren914 is offline
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Default Re: Dyna generator?

The fan has a single diode mounted to it. No need to test as its casing has come apart. It appears to have B1369 written on it. The top line is unreadable. I'll have to find a high voltage / high current stud mount replacement diode to go in its place. Everything else looks good\

I'll order an NTE5824 replacement.
12A average current, 1kV PRV, and the same size stud mount.
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Old 02-13-2011, 09:09 AM
Warren914 Warren914 is offline
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Default Re: Dyna generator?

It's alive again. NTE5890 diode replaces the original. It needed the drill to flash the field, but is making lots of electricity. So far it's been running with a 2kW continuous load for about 15 minutes. The engine sputters occasionally but I'll let it run for another hour or so. Then I can put the fuel tank and electrical panel back in place. Presently operating with a siphon from a gas can and temporary 120VAC split outlet.

Not sure why I need another generator but could be a good loaner machine or backup for my 7000EXL. Still waiting on new AVR and carburetor parts to put the ColemanPowermate back together.
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Old 02-13-2011, 11:46 AM
Wayne 440 Wayne 440 is offline
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Default Re: Dyna generator?

Quote:
Originally Posted by Warren914 View Post
It's alive again...Not sure why I need another generator but could be a good loaner machine or backup for my 7000EXL...
A bit off topic, but some advice. NEVER loan out a generator, unless you are willing to deal with not getting it back in the same condition it left in.

My solution- I don't loan out generators, I sell them. After the need passes, the buyer can bring it back in whatever condition it is in and I'll offer what the set is worth. The money is not a deposit, it buys the generator outright.

Since I started this policy, I haven't "sold" many generators, but the ones I have so far have either stayed with the new owner or returned full of oil and in operating condition and were "bought" for the same price.
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Old 02-13-2011, 06:04 PM
Warren914 Warren914 is offline
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Default Re: Dyna generator?

I seldom loan out equipment for that reason. This is somewhat a beater generator, I bought it for super cheap so not much lost if it goes missing and should be easy enough to fix if it gets broken.

Last time I loaned a generator was about 7 years ago. My neighbor used it for almost 2 weeks after a hurricane tore the lines off his house. It was returned full of gas, had a liter of oil for the next change, a full bottle of fuel stabilizer, and two bottles of wine. That's just the way it should be.

My backup generator is another story. It doesn't go past the driveway.
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