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Author Topic: induction motor as generator fail  (Read 11708 times)

gusbratz

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Re: induction motor as generator fail
« Reply #15 on: April 10, 2017, 11:28:25 PM »
Well I got it working, after quite a bit of trial and error (2) 20uF caps between 2 legs and (3) more between the other leg. Yields about 250v no load then when I fire up a hand held grinder the voltage drops down to 110. If I grind real hard and stall It out the v drops off to nothing and the field collapses. It is weird to watch the frequency/voltage go all over the place as you grind hard then let off and restart it. Not my cup of tea and my curiosity is satisfied. It could work tied into a grid where you get a real steady load and have everything dialed in but for a stand alone generator that I  want to just plug stuff in and have it work it is no good. I didn’t realize it would be so wild with the fluctuations. Never the less thanks for all the help getting it going but now I have to find something else to do with this little engine.

BruceM

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Re: induction motor as generator fail
« Reply #16 on: April 11, 2017, 10:11:33 PM »
Nope, not BruceS.  I'm Bruce M.

dax021

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Re: induction motor as generator fail
« Reply #17 on: April 12, 2017, 02:27:51 PM »
Hi Glort, would you mind posting that link to your post on WMO?  I am still toying with this idea, and want to find out more.  Thanks

LowGear

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Re: induction motor as generator fail
« Reply #18 on: April 12, 2017, 04:44:36 PM »
Quote
One of them was NOT that you are a very nice and helpful guy and the other one is a bit of of a follower of a  greenwashed, self centered pathetic coward hell bent on pushing his own agendas, admin..... but is into electronics and DIY power.

Quote
I put the knife into the said greenwashed Admin yesterday by recommending this site and doing a long post extolling the Virtues of generators running on waste oil to a guy asking about off grid setups.



« Last Edit: April 12, 2017, 04:46:35 PM by LowGear »
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dax021

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Re: induction motor as generator fail
« Reply #19 on: April 14, 2017, 02:01:53 PM »
Thanks Glort, yeah, I've read most of Ed's posts too, but without his vast knowledge on all things mechanical, I am far too timid to experiment on my Lister (yet!!).  I am offgrid and a failure would be the end of me.  He lives about 500Km's from me, and as soon as I get the opportunity, I would love to go visit him and "steal with my eyes"

buickanddeere

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Re: induction motor as generator fail
« Reply #20 on: March 15, 2018, 02:13:47 AM »
I have heard the urban legend of an induction motor as generator for years, I have a little pamphlet from lindseys bookstore entitled "alternator secrets" I bought in the 90's. I also used info from this link http://www.redrok.com/cimtext.pdf. well I set up a nice 3 phase 5hp 1725rpm motor coupled to the little 4hp lister LR1 I bought over the winter. made a nice base and used the doghouse from my ST head that I removed. wired it up in Star and it did nothing. waited for caps to come in the mail and added (3) 25uF caps in delta on the 3 legs and still nothing. Flashed the field and nothing. I wanted to use Star with the center connection as the neutral.  Just for kicks I rewired the motor in delta and hooked up the caps. started it up and the light on the doghouse lit right up. I thought that was cool so without a second thought I throttled her up to 1800 rpm and boom boom out go the lights followed by one of the caps being on fire. shut it down and  then in put the 20uf caps I bought as backups on and tried again. this time just idling It maks about 150 volts and if you give it any rpms the voltage goes way over the scale of the meter.  what is the deal? you supposed to add load and caps a little at a time as you load the motor as a generator? any body got experience with this? pics to follow if anybody is interested.

 Free standing induction motors with caps do not make a good generator. They have to be connected to the utility grid and driven faster than synchronous rpm.   

veggie

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Re: induction motor as generator fail
« Reply #21 on: March 15, 2018, 01:59:16 PM »
The project I'd like to see is the inverse of this one; turn the ST-3 or ST-5 into a starter motor, which will then got back to being an alternator.

BruceM,
Now THAT ! would be a very useful item. A startomatic ROID.  :D

Is that even possible?
Please keep us posted if you proceed with such a project.

Veggie

(I have a spare ST3 kicking around)
« Last Edit: March 15, 2018, 02:06:23 PM by veggie »
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BruceM

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Re: induction motor as generator fail
« Reply #22 on: March 15, 2018, 03:15:41 PM »
It is possible but the poor quality of the ST's being imported into the US is such that I won't waste my time on them.  12V motor generator units are available for $100., so that would seem a practical off the shelf solution to starting, besides adding an auto 12V starter to the generator.

veggie

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Re: induction motor as generator fail
« Reply #23 on: March 16, 2018, 01:23:59 AM »
BruceM, you are right, adding a charger/Generator is an easier task.
This is my Start-o-matic Roid...
Hand starting that thing bothers me as I get older.
https://www.youtube.com/watch?v=qbcbuygYJdM&feature=youtu.be

The generator keeps the starter motor nicely charged for future starts.
The important thing is to ensure that the generator is spinning at least 3000 rpm in order to reverse enough juice to charge the battery.

Veggie
« Last Edit: March 16, 2018, 01:29:16 AM by veggie »
- 6/1 GM90 Listeroid - Delco 33si Alternator
- Changfa R175 - Lease/Neville Alternator
- JiangDong R165 Air cooled - 2 kw
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mike90045

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Re: induction motor as generator fail
« Reply #24 on: March 16, 2018, 02:25:57 AM »
I see that starter/generator is a pretty hefty load, by the speed the engine winds down,  how much load can the engine drive in addition to the s/g  ?    2Kw ?

veggie

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Re: induction motor as generator fail
« Reply #25 on: March 16, 2018, 02:49:46 PM »
I see that starter/generator is a pretty hefty load, by the speed the engine winds down,  how much load can the engine drive in addition to the s/g  ?    2Kw ?

mike90045,

In that video the engine winds down quickly because I do not activate the decompression lever until it's almost stopped.
That is my normal procedure.
When I kill the engine fuel rack, any load from the generator drops away exponentially as the Generator rpm falls below 2500 and electricity production falls away. As the rpm continues to fall below 1500 rpm the generator switches to "Starter"mode and pulls power from the batteries. At that point the user flips the switch which disengages the starter/generator.
To automate this, the toggle switch can be replaced by a relay, and a servo or actuator could be fitted to the decompression lever.

The Generator only produces about 20 amps max. and the load on the engine is only there unit the charging battery is full.
The voltage regulators takes care of that.

Veggie
« Last Edit: March 16, 2018, 02:51:29 PM by veggie »
- 6/1 GM90 Listeroid - Delco 33si Alternator
- Changfa R175 - Lease/Neville Alternator
- JiangDong R165 Air cooled - 2 kw
- Changfa S195 (Waiting for a project)

cujet

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Re: induction motor as generator fail
« Reply #26 on: March 23, 2018, 09:46:23 PM »
...but now I have to find something else to do with this little engine.

The answer seems clear. Install a quality generator head.
People who count on their fingers should maintain a discreet silence

gusbratz

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Re: induction motor as generator fail
« Reply #27 on: March 26, 2018, 09:16:44 PM »
I already have my listeroid with 10kw ST head so it seemed like a waste to build another generator. I sold it to my boss and he is having fun with it now.