Robin Generator - No power

[alchemysa]

Hello all. I picked up this Robin 2KVA / 240volt Generator for $50. The Robin 4 stroke engine starts and runs quite well but its not providing any electricity. (I was told before purchase that it didn't work). I think it has a 'Waikin' generator but I can't find any info on that brand.

How can I test this thing to see if its repairable? First step I guess is to see if the gen is producing any raw juice. The generator has four wires running from the 'dynamo' (is that what its called?) to the control box. Red, black, white and green. Other than getting one of the kids to stick his tongue on these wires how do a test to see if they are 'live'.

Step two I suppose is to see if the control box is usable. Pic 2 shows the inside of the control box (upside down). Apart from dust and cobwebs its pretty tidy except for the obvious burnt or broken part on the circuit board thats encased in plastic. Does anyone know what that bit does and whether it can be repaired? (Or does the whole board need replacing).

This is a bit of a 'project'. I won't be shattered if I cant fix it but I'd love to get it working again. Any help would be appreciated.

 

[Egon]

Sounds like you should be out buying a meter for testing first off.

 

[alchemysa]

Sounds like you should be out buying a meter for testing first off.

Egon. I've got a multimeter but I dont know what I'm supposed to do with it in this instance.

 

[tallyho8]

Just try the voltmeter on any 2 wires, red & black, red & white, etc. The red and black are usually the 2 110 volt wires and the white a neutral and the green a ground but they may be different in that generator. If you get 220 volts on any 2 wires, then it is working and those are the hot wires.

 

[tommu56]

alchemysa

Has it been sitting long?
If so find the wires to the slip rings and brush holder on the armature (actually rotating field)

See if the rings and brushes are making contact are making by un hooking the wires to the brush holder and Ohm between brushes.
It should be low less than 100 ohms if higher clean the oxidizaion off the slip rings and check the brushes to see if they are worn.
After that is ok

Hook a new wire each wire going to each brush holder I run them out through cooling hole away from the rotating parts. Reassemble every thing
put your meter on dc volts at a high range start engine up and see if there is any voltage there. if not hook one up to - on 12v battery and then tap (that is touch it only for a second or so) to the + post.

Then check to see if its giving you an out put.

Leave wires there just tape or wire nut them up for future use.

tommu

 

[Egon]

If, like me, you really do not know where to hook up the testing equipment it might be better to let a good shop evaluate the whole thing!

 

[bbirder]

Sounds like it may need to be excited. Try this link for instructions.
Precise Engine Repair - Small Engine Parts and Information

 

[Skyco]

Flashing the field was gonna be my suggestion too. That PER website has a method of doing it I've never heard of- using a drill! the exact link is here-

PER Notebook - Generator Field Flashing

 

[RonMar]

Flashing the field probably won't do much good with that burnt component on the regulator board. There is only those 4 wires between generator housing and box? I would have expected 5 or 6(two hots, neutral and maybe a ground, as well as the 2 leadsto feed the field winding). That burnt board is most likley the voltage regulator. It takes a little of the generated power and sends it back to the rotating field via the aformentioned brushes or a separate induction coil. The amount sent back, controls the amount of voltage generated. IF that part is smoked, you might have a hard time finding just what that part is to replace, and what caused it to fail also. And as voltage regulators go, it would probably cost as much for that regulator board, if you can find it, as for a newer replacement generator...

Good Luck

 

[bbirder]

I agree with Ron. Sorry, didn't look at the pics or read the post thoroughly. Flashing probably wont help. I have a perfectly "good" gas powered ac-dc welding machine that has a circuit board fried like that. They want 1000 bucks for a new board. Makes you sorry you bought it in the first place.

 

[Skyco]

I agree with Ron. Sorry, didn't look at the pics or read the post thoroughly. Flashing probably wont help.

Oops me neither And I agree flashing isn't gonna help.

 

[Soundguy]

Yep.. looks like a popped transistor.. or regulator or diode in a to-220 package..

If'n ya could find a schematic, ya might be able to get that component from mauser/MCM and desolder it after chipping it out, assuming there are no other faults and it was just a component failure.. if it was a cheap component.. I'd risk it at this point..

soundguy

Flashing the field probably won't do much good with that burnt component on the regulator board. There is only those 4 wires between generator housing and box? I would have expected 5 or 6(two hots, neutral and maybe a ground, as well as the 2 leadsto feed the field winding). That burnt board is most likley the voltage regulator. It takes a little of the generated power and sends it back to the rotating field via the aformentioned brushes or a separate induction coil. The amount sent back, controls the amount of voltage generated. IF that part is smoked, you might have a hard time finding just what that part is to replace, and what caused it to fail also. And as voltage regulators go, it would probably cost as much for that regulator board, if you can find it, as for a newer replacement generator...

Good Luck

 

[alchemysa]

Thanks for the info fellas. I touched a multimeter to the wires circled. In AC mode I got 6 and 15 volts from a couple of the wires. I guess thats nowhere near enough so when I get a chance I'll check the brushes and anything else I can see. If I can get an improvement there without too much trouble I'll move on to the regulator board. If I can't get a schematic or a cheap replacement I'll chip away at the board and see if I can get the blown component identified. I have no great investment in this so, yes, I can afford a little experimenting. I'll let you know how it goes.

 

[RonMar]

Without excitation, that output voltage sounds about right. I am guessing that you got voltage on 2 of the wires? What you were seeing was excitation output from the stator windings, caused by the residual magnetism in the iron core of the rotor. That regulator board would take that small output, rectify it into DC and send it to the brushes/rotor field winding to build on that magnetic field. More magnetic field = more voltage output, so the voltage output would start to increase. At some point, the regulator board will see the output voltage it is looking for and start to limit the current it sends back to the rotor field windings and hold the output voltage at it's regulated point. In a properly operating generator, this startup only takes a second or perhaps less once you get the generator spinning.


Is this strictly a 120V generator, or was it designed for a 120/240V output? If a 240V capable generator, you might find that when measuring from one of the hot wires to the case, you get 1/2 the voltage you see when measuring across the two hot wires.

 

[alchemysa]

Without excitation, that output voltage sounds about right. I am guessing that you got voltage on 2 of the wires?

RonMar. I should have mentioned that the Robin engine was running at the time - but I think thats what you meant anyway. (I don't think you meant that it was residual voltage stored in a stationary generator, like a battery).

So, thats good news I think. Maybe with a clean up and some new brushes (if they are available) I can move on to trying to repair or replace the the regulator.

Yes I just got voltage on two of the wires, and yes its strictly 240v.

Thanks.

 

[Soundguy]

The component you are trying to ID looks to have had the front of it's case blown off.. unfortunately, that is where it's ID info would have been. A schematic / parts list would be of great help here. as I said.. could be a diode, transistor, ets, in that package..e tc.

Quite honestly, i wouldn't invest a dime in doing anything else unless I got the regulator board part first... why go to the trouble of checking / changing brushes if the regualtor is a lost cause... kinda like pulling a car out of a junkyard and changing all the tires and wheel bearings before you try to get the motor unstuck and running.

soundguy

 

[alchemysa]

Quite honestly, i wouldn't invest a dime in doing anything else unless I got the regulator board part first...
soundguy

Agreed. I'll just inspect the brushes for now. Then I'll have a chip around on the regulator board to see if I can expose/identify the part. I can borrow one of those Dremel gizmos. Maybe that will be useful. (It'll be like a little archealogical dig!) Theres a small engine/pump/generator place only about 1/2 a mile away so I'll take the board in there for some advice if I think its worthwhile. I didn't want to go that way until I'd established a few basics.

Thanks

 

[Egon]

A shop with some knowledge, and they do exist, would be your best bet and much cheaper in the long run!

 

[alchemysa]

I said it would be like an archealogical dig and it was! Heres the 'find'.

Before I take it to the 'generator shop' and get laughed at does anyone want to hazard a guess what it is?

I had no idea what a to-220 was so i had to look it up.
TO220 - Wikipedia, the free encyclopedia.

(P.S. Why do so-called experts always think the obvious answer to anything is to buy a new one for a $2000 instead if spending a few cents trying to fix the old one?)



WOW..Thumbnails!. Thats new!!!

 

[Eagleview]

The component on the right is a $2 transistor it could be a voltage regulator or a rectifier you will buy from Tandy or Jaycar . But what caused it to blow ? If your lucky the generator was overloaded and that may be all that is wrong with it . Can you see a partial number on it ?