OT - Generator

[Sonny]

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 luck.

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. Sonny

[Morris Dovey]

I'd suggest also checking news:alt.energy.homepower

[Paul Franklin]

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.

HTH,

Paul F.

[Wayne K]

[Nova]

I never knew about this. Thanks for the heads up.

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"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 the generator:

• Plug the electric drill into the generator receptacle. (Cordless drills do not work) * If the drill is reversible, move the direction switch to the forward position. * 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"

Source:

[Mike Marlow]

Mine has often sat for well over a year - never heard of any such thing and never had to do anything but fire it up.

[Mike Marlow]

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.

[RLM]

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.