My Dayton generator (5000 watt, model SU934, at least 10 yrs old)
isn't working (no electricity at the sockets), yet the Briggs &
Straton motor runs fine. I would assume if the generator is turning,
then power is being produced. I've tried the reset button with no
Can anyone give some advice as to what maybe to check, repair,
replace, etc. With the hurricane headed for the Gulf, I need to get
preparations in order.
Thanks for any help.
How long has it been since you used it? Small generators are
self-excited and rely on residual magnetic field to start the
generation process. If you don't run them once in a while, the field
can decay to the point the generator won't generate. How long is once
in a while? Varies on size/model/manufacturer. But if it's been 6
months or more, could be the problem. Search for "flashing a
generator" or generator field flashing for info on how to fix.
I never knew about this. Thanks for the heads up.
"Field Flashing of Portable Generators
This tip comes from the Briggs & Stratton Customer Education Department
via Precise Engine Repair web site.
As an alternative to flashing a rotor winding with a battery applied to
the brushes, an electric drill may be used. Follow these steps to flash
* Plug the electric drill into the generator receptacle. (Cordless
drills do not work)
* If the drill is reversible, move the direction switch to the
* Start the generator
* While depressing the trigger on the drill, spin the drill chuck
in reverse direction. This will excite the field and the generator will
now produce electricity. If spinning the chuck one direction does not
work, try spinning the chuck in the other direction as you may have the
reverse switch positioned backwards.
Use caution not to get your hand or other materials caught in the chuck.
As soon as the field is excited, the generator will produce power and
the drill will turn on.
The reason this works is because the electric motor in the drill will
act as a small generator when spun backwards. The magnets in the drill's
motor induce a voltage into the motor windings, which is fed back
through the trigger, cord and into the generators receptacle. From there
it goes into the power winding of the stator. The voltage going through
the power winding creates a magnetic field, which is intensified due to
the iron core of the stator laminations. The rotor intersects this
magnetic field as it is spun past the power winding, thus inducing a
voltage in the rotor winding. Once current flow is present in the rotor
winding the rotor has been flashed.
If flashing the field does not make the generator work, you may have
additional problems, besides a lack of magnetism in the rotor. Further
testing will be needed. Hopefully, this will give a simple way to field
flash your generator if needed - Bruce Perrault"
Aha... having already replied to this once, I then did some googling. Turns
out this is what we used to refer to as polarizing a generator. Was a
common thing on old automotive generators, but you generally only did it
once - when you first installed one. Have never experienced a generator
losing it's magnetic field. I suspect one would have to sit for much longer
than just a few months for this to occur.
I have a pdf document for my 3.5KW generator that shows how to flash the
field in fig. 6-11. If you want me to send you a copy of the pdf doc. it
is 4.3mb. Drop me an Email to rlm4848atyahoo.com with Generator in subject
line and I'll send it.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.