4000W Generator Troubles

[jgarrett]

Generac Co.
Model# 05513-0
Series s4041
Serial# 1053615
Motor 8hp Briggs&stratt

so i got a generator in pieces from a buddy of mine that tried to fix it. i got it running but am still getting no voltage. I have read several different ways to flash the head......but there is a little circuit board that im not sure about. Oh and i cant find the manual......generac denies making this model. Any help on how to troubleshoot this ? i am new to generators so please keep it basic. thanks

[Wayne 440]

Basic trouble shooting guide for small portable Generacs-

(a) Start and verify that the engine is operating properly.

(b) plug known good 120v load (light bulb, toaster, fan, coffee pot etc.) into output receptacle.

(c) If load doesn't function, run it over with something big and heavy, then discard the set. (unless you may need the engine for something else)

Seriously, unless you can gain more than "basic" knowledge, that is about all you can do, with no diagram and (presumably) little experience with generator repair.

If you will answer these questions, maybe someone here can help

(1) Can you tell us if your set has brushes or not?
(2) Have you actually checked the voltage with a meter? (0 volts and 6 volts look the same when you plug a lightbulb in, but the readings can indicate much different troubleshooting paths)
(3) Is the engine running at near proper speed? (probably 3600 rpm or so)
(4) Is there a capacitor any place in the generator end?
(5) how many wires out of the board you refer to, and where are they connected?

[jgarrett]

The board has four wires........and yes it has brushes. I have small engine knowledge...... I have heard flashing with ac and dc. Which is the correct one to use

[K D Redd]

Flash with DC. Try to determine the polarity of the brushes and connect there. A 12 volt battery or battery charger will work.

Kent

[Fred M.]

Originally Posted by jgarrett

Series s4041

JG-

According to the Clymer "Small AC Generator Service Manual", Volume 2, the Series is S4014.

The circuit diagram is quite simple. The "board" you mention is probably a Bridge Rectifier that feeds the field via the brushes. If so, the white wire goes to the positive brush, the black wire to the negative brush.

The Stator has a blue and a red wire feeding the Bridge Rectifier. I would guess they are smaller guage than the other three that feed the AC Output.

The 240 Volt stator leads have Gray to Neutral, with Blue and Red feeding the two circuit breakers.

Does this look like what you have? Note that the 120 Volt outlet has one tab broken off, since each half is fed by opposite sides of the 240 Volts. If the outlet had been changed, the tab would be a direct short circuit across the 240 Volts.

Fred

[jgarrett]

what happens if you get the polarity wrong when flashing?

[jgarrett]

the two smaller tabs are for the red/blue wires going to the stator......does it matter how they are connected one tab is marked with an E.....thanks

[jgarrett]

heres some pics

[smallen]

this unit was built by generac portable products now owned by briggs & stratton
any info or parts will come from a briggs dealer

the positive brush is the one closest to the bearing
the small blue/red are the dpe winding, a/c volt, does not matter which terminal
brush terminals are marked + - on rectifier
put 12v dc to brushes for a few seconds to flash winding, with rectifier unplugged
measure a/c volt at red to blue wire while flashing, should have 60 volt a/c or above if windings are ok
if no output during flashing do a resistance test on rotor and windings
Red to blue
Red to gray
Red to blue (small pair)
Check each wire to ground

[jgarrett]

i put 12vDC on the brushes without the rectifier connected i got no voltage anywhere......i did get an arc when i disconnected the power source.......any ideas

[smallen]

disconnect the red wire from the frame for testing

red to blue .37 ohm
red to gray .37 ohm
dpe red to blue 1.5 ohm
rotor across slip rings 24 ohm
all wires will be open to frame set on meg ohm scale

[jgarrett]

tried to flash no voltage

these ohmed as being together
red to blue
red to gray
small red to small blue

small red &small blue did ohm together but not to the red ground that is bonded to the head

[jgarrett]

red to blue .8
red to gray .8
dpe red to blue 1.4
brush to brush 38.2

[jgarrett]

ok i tried flashing it again and i think it worked.

i put 12vDC on the brushes with the motor turning and i got 50ish volts to ground but..........
problem i stopped everything and put the rectifier in place and i got 3.8-4.2 volts
does this indicate a bad rectifier bridge or something else.

[smallen]

check dpe red to blue winding with 12v to brushes, if voltage is 50v ac or above, replace rectifier

[jgarrett]

i think i may have had a breakthrough i looked at new rectifiers and saw a green wire comming from the board.......as you can see on my pictures it has been snipped on mine.......could this be the problem

[smallen]

no the green wire is for a field boost option, not used on your model

[jgarrett]

Is there any way to check the rectifier?

[jgarrett]

Is the dpe wire the small one

[BTPost]

Yep, you will need a Resistance Measuring Device, like a Volt Ohm Meter. Diodes only conduct in one direction, so the meter should read continuity in only one direction and OPEN in the other.... If it reads OPEN in both directions it is BAD. If it reads Continuity in both directions it is BAD. A Diode Bridge is a block with four diodes in it. It has two AC inputs and a Poitive and Negative Output. You can measure each of the four diodes, by checking between each ot the adjacent connections.