# Rectifier on a starter



## Brianjr (Feb 5, 2016)

I must say this sight is awsome,,i posted about my snowbird n a belt problem,,it is fixed n worked great today in 46 cm of snow,,,so now i would like to get the electric start going but the wires or off,i guess its a rectifier from my reasearch n i have no idea how to hook it back up,,help again you guys are wicked


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## Kiss4aFrog (Nov 3, 2013)

How about a photo or two ??


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## detdrbuzzard (Jan 20, 2012)

never heard of a rectifier on a starter


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## db9938 (Nov 17, 2013)

Wouldn't it be an inverter, maybe?


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## detdrbuzzard (Jan 20, 2012)

db9938 said:


> Wouldn't it be an inverter, maybe?


I would like to see a pic of the starter


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## Brianjr (Feb 5, 2016)

Me either but i thought maybe becuz its a snowblower,,,this is how i took it off,,,,i should be able to plug it in n punch the button i would think the number on the rectifier is br252








View attachment 78857


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## Vermont007 (Mar 29, 2015)

That looks like a Briggs & Stratton 12 Volt DC Starter.

Most SnowBlowers use 110-120 Volt AC Starters.


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## Kiss4aFrog (Nov 3, 2013)

You need to take better photos. The square thing is a rectifier for converting AC input into DC output.

What are the numbers on the starter itself ?? Part number ??

Was there any more to the wiring ??

IF , , , it's a 12 volt starter it might have had a 120 to 12 volt transformer that put out AC and that rectifier was used to convert the AC into DC.

But if so that wiring on the starter is terribly small to try and carry the current a 12 volt starter would use. The lower the voltage the higher the amperage to get the same job done, thus the thicker the wire.


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## brickcity (Jan 23, 2014)

detdrbuzzard said:


> never heard of a rectifier on a starter


me neither but I never really thought about it.
obviously if the starter isn't using a dc battery for power it needs a rectifier


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## skutflut (Oct 16, 2015)

If it is a dc starter, it would also need a stepdown transformer from 120 to 12 volts, which would be a pretty good sized chunk of iron to supply the DC load current.


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## Blackfin (Jan 25, 2016)

Better pic of the starter label please. If I zoom in I think I see "120 VOLTS" but would need a better pic to be sure.

This looks like a bodge to me, to be honest. Maybe someone thought you could hook a battery up to a rectifier and get 120VAC out. It probably once looked like this:










but now looks like the mess you've got. From the image it looks like someone took a saw or dremel and hacked the AC mains receptacle out of the plastic cover (is the switch still there?)


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## Grunt (Nov 11, 2013)

detdrbuzzard said:


> never heard of a rectifier on a starter


Old Toro S-200 snow blowers used the same setup with a rectifier in the push button box. Not sure why, but it converted 120 volts AC to 120 volts half wave pulsed DC ?

The white wire from the extension cord or neutral prong in the receptacle on the starter goes to the rectifier terminal with the white arrow.

The black wire from the extension cord or the positive prong in the receptacle on the starter goes to the push button switch terminal marked with the blue arrow.

Oh, the green wire with no terminal goes to the ground prong on the starter receptacle.


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## Blackfin (Jan 25, 2016)

Grunt said:


> Old Toro S-200 snow blowers used the same setup with a rectifier in the push button box. Not sure why, but it converted 120 volts AC to 120 volts half wave pulsed DC ?


That's interesting. The circuit shown is a full-wave rectifier so it looks like that starter setup is getting straight DC.

I found a pic of a starter for the S-200 online and see it marked as "28-9140 ... American Bosch ... 100 V.D.C." So it's a DC motor.

I think the OP's starter is AC. Maybe someone saw that schematic and thought that's how it should be wired.

Who knows. Wonder if the OP coming back?



> Oh, the green wire with no terminal goes to the ground prong on the starter receptacle.


Good point. Anytime AC mains is connected to equipment like this the green ground wire should be connected to the equipment and to the 3rd prong in the AC outlet. There's a pretty good electric shock hazard without that ground made.


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## bad69cat (Nov 30, 2015)

Just learned something new! I never paid any attention to the starters on the old 200's I guess. Usually the gear was plastic and got worn, but they held up good otherwise. They don't sell well now days - so I quit fixing them. Good machines for lightweight dependability.....


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## Grunt (Nov 11, 2013)

bad69cat said:


> Usually the gear was plastic and got worn, but they held up good otherwise.


I just removed the electric starter from a running S-200 I had to put on my friends low use S-200. He got it from a neighbor who used it for an hour total since 1980. Someone tried starting it and fried the commutator and brushes beyond repair. Since he has a pace maker in his chest, I gave him my starter. The fuel line and diaphragm also had to be replaced because of dry rot. Good little blowers for what they are, but as you said, no money to be made flipping them.


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## bad69cat (Nov 30, 2015)

the guy's that buy them are usually roofer's or crews that get hired to remove snow from rooftops that have to hand carry them up ladders. Not a better machine out there for that job. I used to weld up the mufflers since the factory only tack welded them, and beef up the axle mounts too. That made the frames much stronger. We don't get the snows we used to so everybody has forgotten how nice they are for that.......a lot of Walmarts were saved by Toro's!!


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## Brianjr (Feb 5, 2016)

This is the sticker on the starter,,,,,u guys,,,,, man i just cut another 30 cm of snow,,,,last week i couldn't get the belts on 👍👍


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## Grunt (Nov 11, 2013)

Brianjr said:


> This is the sticker on the starter


That just means it requires 120 volts AC 7.5 amps input to run. The rectifier converts it to 120 volts DC output to the starter. Have you tried connecting the wires to the rectifier yet to see if the starter is good?


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## Brianjr (Feb 5, 2016)

Power goes to the starter just fine it blowes the breaker,,,i dont wanna ruin the starter thats why i would like to get some more info on it


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## Brianjr (Feb 5, 2016)

I just need to no ,,on the rectifier it has ac with arrow is that wat i hook white n black from my house to ??


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## Grunt (Nov 11, 2013)

Does your plastic cover with the decals on it have the three prong receptacle for attaching an extension cord to it and a push button that goes over the starter switch? Does it look like the picture Blackfin posted?


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## Brianjr (Feb 5, 2016)

This is it,,,thensame thing


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## Brianjr (Feb 5, 2016)

It looks the same as blackfin posted,,,i appricate ur patience for a dumb ass lol,,,i am posseced with this machine,,,i seen wat it will cut threw


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## Grunt (Nov 11, 2013)

Brianjr said:


> This is it,,,thensame thing


This is the rectifier. Need to know if the plastic cover with the decals has a receptacle in it. Your not dumb, your new. We all started out the same way, so don't be afraid to ask questions. There is "always" someone here to help when needed.


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## Mr Fixit (Nov 19, 2013)

Using this bottom diagram you can test this rectifier to see if it's performing or shorted out. Note the + symbol, the -, AC, and before removing your wires, orient everything on paper for later reinstall. If you have an ohm meter (100 Ohm scale) you can check it in 5 minute. Inside the body is 4 simple diodes you must check for forward and blocking performance. So that requires 8 changes of the black and red leads to verify it's good. For each diode symbol you first need the red lead on the back of the (FIRST) triangle > and black on the I end. A Ohm meter ( 0 )short says it's ok as passing current. Now reverse black and red leads to prove it blocks current flow backwards. You should measure as an open connection this direction. Repeat that for each of the four diodes inside using this diagram. Any differences equals a bad rectifier. They fail a lot.


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## Waterlooboy2hp (Nov 29, 2011)

Brianjr said:


> This is it,,,thensame thing


==========================================

A few years ago, I needed a missing starter, for a 1965 Jake, that I bought, as well as some other parts. Bought a 1974 parts machine, that had everything I needed.

The starter did not run, because 1 of the 4 diodes in the rectifier was burned out. The diodes were no longer made. I called Digi-Key and explained my problem. They came up with a 40 amp rated rectifier like yours as a replacement. This is the way I wired it up. ---










The starters looked like this.---










The box on top, had the rectifier side, sealed in with epoxy and had to be gutted out on my milling machine with a carbide cutter. This is what my replacement looks like.









These starters fit in Tecumseh h60 engines as well a few other Tec models. I only needed 1, but wanted a spare. Found a working one on E-bay and bought it. A asked him, if he had any non working starters like it. He had a box full in the back of his shop. Got 7 more starters for a song. In the end, 3 of them needed rectifiers and the other 4 , only minor repairs. Needless to say, my need for a challenge, has left me with a self full of starters. --- John


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## Blackfin (Jan 25, 2016)

Briggs' L-head manual shows the internal arrangement of the control box as follows:










That motor looks then to be a 120V _DC_ motor even though the starting system itself is 120VAC. The presence of the full-wave rectifier means that motor is running on DC. 

OP, your picture of the motor is disappointingly blurry and the part number is basically unreadable. "396488"? I dunno. At any rate, the marking on the motor itself "120V 60 cycles" is still weird to me as it suggests either an induction motor or an internal rectifier but the Briggs manual showing permanent magnet housings suggesting DC operation of the motor itself.

Anyway, hopefully the wiring layout above gives you some assistance.


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## Brianjr (Feb 5, 2016)

You guys are simply amazing,,,,with all this info i will figure it out,,,i will post with a update,,,knowledge is the key and man i found it here&#55357;&#56397;


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## Brianjr (Feb 5, 2016)

Sorry but the part is almost unreadable with out a meg, glass #396469


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## Brianjr (Feb 5, 2016)

Brianjr said:


> You guys are simply amazing,,,,with all this info i will figure it out,,,i will post with a update,,,knowledge is the key and man i found it here


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## Brianjr (Feb 5, 2016)

Follow up on the starter followed the wiring diagram for the rectifier to the letter,,u guys rock works perfect thank so much


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## Grunt (Nov 11, 2013)

Good job Brian, I said you weren't a dumb a$$, and now you proved it to yourself. You can do anything if you try.

:goodjob:


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## skutflut (Oct 16, 2015)

Brianjr said:


> Follow up on the starter followed the wiring diagram for the rectifier to the letter,,u guys rock works perfect thank so much


If anybody is interested, here's what goes on in various circuits. 

The first picture shows what we get from a typical DC supply from a snowblower alternator, where they install a single diode in series with the AC output from the alternator. This is used to power an incandescent light or an LED. An LED powered from this source will probably flicker quite a bit due to the dead spots between pulses.


The second picture is what's going on with the rectifier and a filter capacitor. This is a full wave rectifier, which takes the negative side of the AC signal, and flips it over to a positive, and puts it back in the dead spot you see between the half wave rectified output. This full wave output is also double the frequency of the original AC input. The capacitor stores energy which is returned as the amplitude drops off when the alternator is not moving by the magnets. 

The third wave form is full wave rectified AC, without a filter capacitor. That's what it looks like with no load. As soon as you add load to it, that form changes quite a bit, which is why filter capicitors can be necessary, depending on what you are powering. Bigger caps store more energy which gives better damping on the valleys.


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## 404 (Feb 1, 2015)

Yes, also in figure 2 the size of the ripple or droop depends on the current drawn from the circuit. With no current drawn the ripple becomes very very small.


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